Update: I tested in a new 4.10 project and had the same problem, then I tested in a new 4.11 project and had no issue. I guess this was fixed for 4.11. Our studio will be updating our project to 4.11 tonight seeing as this is a blocker for us, plus the new USplineComponent improvements are much needed too.
Marking as closed, the fix to this issue is to upgrade to 4.11.