Unless you enable Kerbal Experience
That should work fine - I've used it on many a science mode without issues.
This may be a mod problem, I notice you have Custom Barn Kit installed, which is a mod that directly affects building upgrades. Assumably this is for Strategia, which a mod built for Career mode only - I don't know how, but perhaps that's the cause of the issue? Like it's trying to force building restrictions to be on even in Science mode? Might be worth asking on the associated mod threads
GluttonyReaper's post in Kerbals can't disembark on Science Mode was marked as the answer