When trying to activate JWT app, it won't allow "other" expiration time on token

Hello,

Trying to set up JWT app and wanting to establish a far off expiration time. However the options are greyed out. The only time I can get them to not be greyed out is after activation but then the expiration is 90 mins. Trying to adjust with the radio options proves futile because it just returns back to original expiration.

Any ideas?