I think I had the same issue.
In my case, I had an Enhanced Input Event placed in a User Widget and when I compiled and saved that widget I had a log message telling : ‘bAutomaticallyRegisterInputOnConstruction’ must be true in order to use Enhanced Input in the widget…
When I removed the Enhanced Input Event from that User Widget, the error disappeared.
So, to fix the problem, I had to put that Enhanced Input Event in my PlayerController to have it working by calling a Custom Event on the User Widget from the Player Controller Input Event.