TLDR, I think WARP is the problem. At least it was the problem for me
I also had this bug on insanity. I'm playing as a vanguard, and have Tali and Liara in my party. It happened over, and over, and over. Tried quite a few things.
- Installed new graphic card drivers (5700 XT)
- Lowered screen resolution from 4k to 1080p
- Disabled Steam and Origin overlay. Notably, the origin overlay setting appears to only turn it off for the MELE launcher. Mass Effect 1 LE itself is considered a different game, by Origin so the origin overlay is enabled when this "separate" game launches
- Did not use the "tactical wheel" or whatever you call it in order to pause combat and issue commands to allies. I saw that this was a possible fix on reddit, but it did not work for me. Notably, I continued to use all my powers which were hotkeyed and did not require me to use the tactical wheel. This includes Warp
- Tried using only biotic abilities which did not affect gravity (i.e., warp and barrier) after seeing other comments in this thread.
None of the above worked. It was only when I did it without using any offensive abilities at all that I was able to complete the fight. The only difference between the run that worked, and the above one that did not was Warp. So I went back and tried it again using every biotic ability Liara and I had (throw, singularity, lift, barrier, and stasis). Everything except warp. And it worked!
Maybe the bug is caused by warp still ticking down health while the cutscenes are playing?
Google drive link to save. https://drive.google.com/file/d/1D1wWVLhCbL5ZvHjVZvaG0-tI8zqjUz6K/view?usp=sharing