When [[standalone|install/Linux_standalone]] git-annex runs external special remote, it does so in the standalone environment.  I wonder if it makes more sense to run them in the original environment (by restoring PATH from ORIG_PATH)?   If the external special remote has been packaged with a package manager like conda, it expects its dependencies to come from the environment set up by that package manager, not the git-annex standalone environment.

Also, maybe rename exported vars like ORIG_PATH to GIT_ANNEX_ORIG_PATH.
