Grim Fandango OpenGL transparency issues

[arrowgent]

https://bugs.scummvm.org/ticket/12931
similar to the start of the game

Please check you are including all the following information in your bug report:

ScummVM version (scummvm -v)
ScummVM 2.5.0 (Dec 1 2021 22:52:30)
Features compiled in: Vorbis FLAC MP3 ALSA SEQ sndio TiMidity RGB zLib MPEG2 FluidSynth Theora AAC A/52 FreeType2 FriBiDi JPEG PNG GIF TTS cloud (servers, local) TinyGL OpenGL (with shaders) GLEW
-- aquired from a PPA which compiled this version.
​https://launchpad.net/~savoury1/+archive/ubuntu/games/+index?field.series_filter=bionic

Bug details, including step-by-step instructions to reproduce the bug
start game, exit door.
occasionally opengl transparency is broken. not always.
see attached videos at bottom.

Language of game (English, German, ...)
english

Version of game (CD, Floppy, DOS, Amiga, ...)
CD + patch 1.01

Your OS, including version and device if appropriate (Windows 10 build 1709 32-bit, Debian 9.2 x86_64, Android 7.0 on Samsung Galaxy S7, ...)
Linux Ubuntu 18.04 LTS x86_64
Nvidia 1070 Driver Version: 470.86

Attach a save game if possible
not required

If this bug only occurred recently, please note the last version without the bug, and the first version including the bug. That way we can fix it quicker by looking at the changes made.
occurs in several locations of the gameplay
new release v2.5.0

Next, select the game in the 'Game' dropdown, and the game engine or other component in the 'Component' dropdown. Enter your text, and hit the button!
yep.

video clips
​https://clips.twitch.tv/ThankfulSpotlessRadicchioGOWSkull-0Bu2TyOMPHSwweL7
​https://clips.twitch.tv/MistySpikyYogurt4Head-uot_0PsuIYtZLD9u

the worst area is at the forest scenes, driving the car where everything is invisible.
​https://clips.twitch.tv/FrailToughGarageTinyFace-_TmPOdgvaxtIwEko

workaround
can be fixed by saving, exiting to launcher then reloading game
until it breaks again