Currently running both performant and Phosphophyllite on a server and tried using the config to disable the check. Currently Phosphophyllite reads the config but it then resets it so it only lasts for one restart.

This has been fixed in 0.4.5 and the next (not the current) 0.5 alpha. We haven't released a new alpha for 0.5 however, and aren't going to for a bit until some more issues with 0.5 are addressed. In the meantime, we would advise (as the warnings suggest) against using Performant. Thanks for the report!