Not being kept signed in

Trying out Ultimate Member to see if it’s what I’m looking for.

For a few days it worked well.
However, I’ve just discovered that if I do not select “remember me” when logging in, I am immediately logged out. I have to sign in again until it locks me out (until I select ‘remember me’).

I cleared my cache. Same issue. I added all relevant pages to my litespeed cache ignore. Same issue. I’ve disabled litespeed caching entirely. Same issue.

What’s going on here?

https://wordpress.org/plugins/ultimate-member/