GIT_WORK_TREE; a recipe for disaster

I'm using git for windows version 2.25.0.windows.1. Yesterday I was in a bash command line and changed directories to another project. I ran git status and it complained about basically everything being deleted when the files were sitting there just fine. I thought that maybe it is confused since I upgraded git recently and so I ran git checkout -f and git clean -xfd to make sure that the working directory would be restored to a pristine state. I later changed back to the first project directory where I was horrified to see that all of the files from the second project had been checked out, and the changes in that project that I had been working on for a few days had been deleted.

It seems the cause of this is that I had opened git bash from the git gui menu instead of from the windows explorer menu. In previous releases, this cause GIT_DIR to be set ( I believe ), and so that session of git bash was tied to that repoistory even if you changed directories to another repository. I always thought this was rather annoying, but things seem to be worse now that I have upgraded, because git now uses the index and hisotry log etc from the cwd, but compares that index to files elsewhere. This seems like a recipe for disaster. Why does git gui set these environment variables at all, and could it please stop?