Switch from 4.11 to 4.14. Help with networking issues

Hi there!
I’ve been working with a team of students since last June on a shooter game project. We started work on the project using 4.11.2 and have recently upgraded to 4.14.3. We’ve encountered several errors, most of which we have been able to solve on our own, but there is one particularly nasty networking issue that we haven’t been able to track down which seems to leave no errors in the log.

The issue is this (as best as I can tell. The issue changes slightly every time I test again): The host sees everything fine. The first client to join seems to be able to move and function properly until he dies and respawns the first time. Then he appears stuck in place and unable to move or fire his weapon but can only look around (the host sees all of the clients’ actions just fine though). The second client most often is bugged right from when the game starts. He cannot see himself (or others) move or fire or perform any kind of input action. When he dies, that event replicates properly, but his character just ragdolls right where he sees himself standing rather than where he really died.

Just to clarify: all the networking was working properly in 4.11.2 and by reverting back to before the engine upgrade, I was able to make it work properly again, but I would love to be able to use the new engine features. I know that this description of the problem is vague at best, but I’m not sure how to clarify considering that our project is rather large and I’m not sure what blueprints/code to show to help track down the problem. If I can clarify in some way, please let me know.

I’m also on this project and I suspect that a certain error message we haven’t been able to quash may be related:

Constraint attempting to create joint between two objects in different scenes No joint created
None of the links it gives resolve to anything valid, so I have no idea where or what the problem even is. I’ve poked around on other questions, but I haven’t been able to find a definitive/helpful answer