laravel-caffeine dripping but not keeping sessions alive on form pages (L5.2)

I'm working on a L5.2 project experiencing regular TokenMismatchException on posted forms after sessions expire.

I confidently installed laravel-caffeine to resolve the issue but unlike with other projects it doesn't seem to keep the session alive. I can see the caffeine drips working in console but if I submit the form after the session expires it still throws the error:

Things I've checked:

• Forms all have {!! csrf_field() !!}
• Routes all within the web middleware
• The middleware set up is default L5.2 with one additional role checking class
• Same issue is affecting local, stage and production

Any hints on things to try would be very welcome