We witnessed the same error. Seems to be related to the way the path to the temporary file is generated.
Gitlab v18.4.1-ee
Saving cache for successful job
00:00
Creating cache 684-097b7d1b66dca56343bd8d0c01f2e9c64a8df433-build-linux-debug64-2-non_protected...
sh: line 198: /home/ec2-user/builds/rZn2hSXiB/2/INF/INF-CMM/builds/rZn2hSXiB/2/INF/INF-CMM.tmp/gitlab_runner_cache_env: No such file or directory