@jwink3101 I'm curious what happens if you try the same VLC experiment with a normal local file (not mounted via rclone). Does the ModTime still get updated?
I'm interested because I also care about ModTimes and have seen some similar unexplained issues with them when mounting on macOS (and specifically upon unmounting, like you described). More recently I've been wondering if there might be an issue in the VFS layer itself, as I've also seen some odd behavior with rclone serve sftp, which shouldn't be using FUSE at all (but I'm not yet sure whether or not the issues are related).