Have the same problem. Probably related to the bug is that UE keeps showing “Loading Visual Studio” long after VS has started and then eventually opens up a 2nd instance of VS.
This is an instance of a known issue that has been reported here: Unreal Engine Issues and Bug Tracker (UE-51608) . You can track the report’s status as the issue is reviewed by our development staff. Please be aware that this issue may not be prioritized or fixed soon.