When that happens it is very likely that you are actually using UE4’s Default Pawn instead of your own. The Default Pawn has a floating movement component and standard action binding to WASD, hence what you are experiencing.
Check that:
-
If you are using Player Start,
your Pawn class is properly
referenced by your Game Mode within
Default Pawn -
If you are not using
Player Start but have your Pawn
directly in the level, that
Autoposses is set to Player 0
With that it should work as expected.
Cheers,
Marco.