This seems counter to the reason you have keyboard input in the app...
All my passwords are extremely long & complicated. So it's practically impossible to enter them with the remote.
Update: I pulled out an android tablet I use for testing & installed LastPass & Android Tv Remote & it does the exact same thing as the iOS app. I select keyboard input & type or paste & it doesn't insert it into the app on the Android TV.
Mine does goto the text box and double tap the select button but with a Bluetooth keyboard only