Photos
Description
The entire in-game HUD render layer (hotbar, F3 debug screen, chat) renders skewed into a diagonal, mirrored parallelogram instead of sitting flat in its normal screen-space position. The 3D world renders completely normally — only the 2D/orthographic HUD overlay is affected. Performance is unaffected (no FPS drop).
The corruption is continuous and re-applied every frame during gameplay: opening any Screen (inventory, Lunar's mod menu, settings) renders the HUD correctly, but the moment gameplay resumes and the HUD overlay draws again, the skew returns. On closing the game entirely, one single frame renders correctly right before the window closes — suggesting a transform (rotate/scale) is being pushed onto the HUD's matrix/render stack each frame and not properly reset until the render hook unregisters at shutdown.
Steps to Reproduce
Launch Minecraft 1.21.4 (Fabric) with ImmediatelyFast enabled alongside the mod list below.
Join any world/server.
Observe the hotbar, F3 debug overlay, and chat.
Expected Behavior
HUD elements (hotbar, F3, chat) render flat and correctly positioned in screen space, matching the 3D world's normal orientation.
Actual Behavior
The entire HUD is skewed diagonally, mirrored, and offset from its normal position, as if drawn with an incorrect/leaked transform matrix. See attached screenshot.
Troubleshooting Already Performed
Confirmed not shader-related (occurs with Iris/Complementary Unbound/Euphoria Patches fully disabled).
Confirmed not related to Lunar Client's custom HUD/F3 modules (disabled, bug persisted).
Confirmed not Lunar-specific — reproduced running the modpack directly through Fabric with Lunar Client not involved.
Confirmed not OS/driver/hardware-specific — reproduced identically on both Windows and Bazzite (Linux), in both fullscreen and windowed mode.
Confirmed not caused by options.txt (verified clean, no corrupted GUI scale/rotation values).
Confirmed not caused by duplicate/conflicting mod jars (Sodium, Fabric API, Noxesium, Text Placeholder API duplicates all removed; bug persisted).
Ruled out Armor HUD Numbers, uku's Armor HUD, Xaero's Minimap (including with rotation locked), Simple Voice Chat, ReplayMod, Noxesium, FreeLook Mod/Perspective, and Freecam individually via binary-search testing with mods toggled on/off.
Performed a fully clean reinstall of the launcher, mods, and configs — bug still present.
Isolated the cause to ImmediatelyFast by disabling it alone (all other mods, including FerriteCore, Freecam, FreeLook, Full Brightness Toggle, and HealthIndicator, left enabled) — disabling only ImmediatelyFast fixed the HUD completely.
Environment
Minecraft version: 1.21.4
Mod loader: Fabric
ImmediatelyFast version: 1.8.7 (for MC 1.21.4)
Launcher: Lunar Client v2.22.23-2630 (bug also reproduced without Lunar)
OS tested: Windows, and Bazzite (Linux)
GUI Scale: 2
Relevant mods present: Sodium 0.6.13, Fabric API 0.119.4+1.21.4, Noxesium 2.6.2, Xaero's Minimap 1.21.4-26.4.2, Xaero's World Map 1.21.4-1.44.2, Distant Horizons 3.2.0-b, YetAnotherConfigLib 3.8.2, Cloth Config 1.21.4 v17.0.144, Architectury API 1.21.4 v15.0.3
Additional Notes
Given ImmediatelyFast's role in batching immediate-mode HUD draw calls, this looks like a matrix/transform state leak specific to the HUD batching path — possibly triggered by another mod in this list submitting an unusual draw call that ImmediatelyFast's batching doesn't isolate correctly. Happy to provide full mod list, logs, or a minimal reproduction modpack if useful.
Photos
Description
The entire in-game HUD render layer (hotbar, F3 debug screen, chat) renders skewed into a diagonal, mirrored parallelogram instead of sitting flat in its normal screen-space position. The 3D world renders completely normally — only the 2D/orthographic HUD overlay is affected. Performance is unaffected (no FPS drop).
The corruption is continuous and re-applied every frame during gameplay: opening any Screen (inventory, Lunar's mod menu, settings) renders the HUD correctly, but the moment gameplay resumes and the HUD overlay draws again, the skew returns. On closing the game entirely, one single frame renders correctly right before the window closes — suggesting a transform (rotate/scale) is being pushed onto the HUD's matrix/render stack each frame and not properly reset until the render hook unregisters at shutdown.
Steps to Reproduce
Launch Minecraft 1.21.4 (Fabric) with ImmediatelyFast enabled alongside the mod list below.
Join any world/server.
Observe the hotbar, F3 debug overlay, and chat.
Expected Behavior
HUD elements (hotbar, F3, chat) render flat and correctly positioned in screen space, matching the 3D world's normal orientation.
Actual Behavior
The entire HUD is skewed diagonally, mirrored, and offset from its normal position, as if drawn with an incorrect/leaked transform matrix. See attached screenshot.
Troubleshooting Already Performed
Confirmed not shader-related (occurs with Iris/Complementary Unbound/Euphoria Patches fully disabled).
Confirmed not related to Lunar Client's custom HUD/F3 modules (disabled, bug persisted).
Confirmed not Lunar-specific — reproduced running the modpack directly through Fabric with Lunar Client not involved.
Confirmed not OS/driver/hardware-specific — reproduced identically on both Windows and Bazzite (Linux), in both fullscreen and windowed mode.
Confirmed not caused by options.txt (verified clean, no corrupted GUI scale/rotation values).
Confirmed not caused by duplicate/conflicting mod jars (Sodium, Fabric API, Noxesium, Text Placeholder API duplicates all removed; bug persisted).
Ruled out Armor HUD Numbers, uku's Armor HUD, Xaero's Minimap (including with rotation locked), Simple Voice Chat, ReplayMod, Noxesium, FreeLook Mod/Perspective, and Freecam individually via binary-search testing with mods toggled on/off.
Performed a fully clean reinstall of the launcher, mods, and configs — bug still present.
Isolated the cause to ImmediatelyFast by disabling it alone (all other mods, including FerriteCore, Freecam, FreeLook, Full Brightness Toggle, and HealthIndicator, left enabled) — disabling only ImmediatelyFast fixed the HUD completely.
Environment
Minecraft version: 1.21.4
Mod loader: Fabric
ImmediatelyFast version: 1.8.7 (for MC 1.21.4)
Launcher: Lunar Client v2.22.23-2630 (bug also reproduced without Lunar)
OS tested: Windows, and Bazzite (Linux)
GUI Scale: 2
Relevant mods present: Sodium 0.6.13, Fabric API 0.119.4+1.21.4, Noxesium 2.6.2, Xaero's Minimap 1.21.4-26.4.2, Xaero's World Map 1.21.4-1.44.2, Distant Horizons 3.2.0-b, YetAnotherConfigLib 3.8.2, Cloth Config 1.21.4 v17.0.144, Architectury API 1.21.4 v15.0.3
Additional Notes
Given ImmediatelyFast's role in batching immediate-mode HUD draw calls, this looks like a matrix/transform state leak specific to the HUD batching path — possibly triggered by another mod in this list submitting an unusual draw call that ImmediatelyFast's batching doesn't isolate correctly. Happy to provide full mod list, logs, or a minimal reproduction modpack if useful.