The webp portion seems to work fine but the missing tag system seems faulty. The cause seems to be the more sophisticated regex. For example if you look for missing races ass and tits sizes, you'll see elves with big tits and small/big ass. You can work around this by just making custom filters as those seem to work fine. You can also fix it by changing the settings to simple string regex but that will probably mess with compatibility.
Viewing post in Portrait Pack Editor Redux (Not a Mod)
Took me a minute to replicate the bug, but yea, I see it now
Weird bug,
I already implemented custom filters internally, but the "missing checkboxes" were using the Regex instead
Since most of the Regex are the same value as the custom tags, this had escaped my notice
Currently my build doesn't distinguish between Tags, Regex, and Name. All of them are stored as Strings instead. I should enforced strong-type.
Thank you, fixed in 1.98