I am also having this issue. I am new to Enpass and I hope you can get it fixed.
I am running Windows 7
Enpass version 5.3.0.1
Cloud sync is gdrive
I am using browser extension
this happens when i try and use enpass to fill in a password to a browser it will hang for several minutes. Today i was logging into the application itself and got "not responding" for several minutes.
I am using Chrome