I used the custom PHP function heavily. It's creating millions of tmp/regularlabs/customphp files. We discovered it because the server crashed due to running out of inodes.
I'm thinking of setting up a cron job to delete these files intermittently. However, I think this might also be something you'd want to address on your end.
The tmp files created by the PHP class in the Regular Labs library (used for PHP conditions and other PHP based stuff), should be created and then deleted during the same pageload.
If those files do not get deleted, then there are probably file/folder permission issues on your server.
You'd have to ask your host to look into that.