There seems to be no error per se. RequiresMountsFor=%s%s%s..%s%s%s is expanded to
RequiresMountsFor=/bin/zsh/bin/zsh/bin/zsh/bin/zsh/..., which takes a bit of time,
and then we iterate over this a few times, creating a hashmap with a hashmap
for each prefix of the path, each with one item pointing back to the original unit.
Takes about 0.8 s on my machine.
