A pen drive was in my bag by mistake, and I submitted it during the scanning process. Will any action be taken in this situation?

It is against the policy , if it's find by them with any documents with tcs saved . Can do anything, generally they will declare and let you go.

They’ll tell to submit at dispatch that all

No action will be taken, you didn’t take it inside right?

Don't worry it's not a crime . Nothing will happen

As you have submitted it before entering then no problem should happen