It's quite typical to have multiple working directories, but mach try fuzzy only keeps one cache. Today, I tried to push with fuzzy from two working directories with different taskcluster/ci configurations (and yet different from m-c). What happened is that the first one worked because it found the changes, but the second didn't have the jobs I expected it to have, because the cache was newer than the taskcluster/ci changes in that working directory, so I was getting the task set from the other working directory.