The bug
I see an approximate 5 second pause at the end of test runs when Xdist is used. During this time the Xdist workers consume about 100% of a CPU core each.
This is cause by syrupy's pytest_terminal_summary hook function being executed in workers, for reasons I do not understand.
I have created a pytest_textual_snapshot PR (Textualize/pytest-textual-snapshot#20) that provides a work-around for this.