Its a small problem, but still:

On the newest plugin Version (v3.1.53) if I use the Web Editor for groups or players and I add time to Expiry, i cant add the permission :/ Only without Expiry time. Thats all

Sorry, I don't understand what you mean.

Can you give an example?

If I use for example /lp user editor and click on the link the Website opens normaly. But If I enter a Permission to add AND an expiry time and press the + it does not work, only if I leave the Expiry box empty.

Alright, I'll look into it.

Please open a ticket here instead though. ;)
https://github.com/lucko/LuckPermsWeb

also by issues?

Yes.