Blueprint replication problems on transition to 4.11

I have converted my project to from 4.10 to 4.11 and most of the things works smoothly (with performance increase, yey!) but I am having an issue with networking. Whenever I play in editor with 2 clients, I get a full crash. I debugged the code, and the error occurs at:

RepLayout.cpp, line 2209
check( Property->PropertyFlags & CPF_Net );

Basically, some replicated properties are uninitialized, probably because replication changed in Character C++ classes. The error occurs for my main character actor. My setup is as follows: Character → ClassBase (C++) → BP_ClassBase (BP) → BP_Fighter (BP).

The error goes away when I open BP_ClassBase and recompile, but it is still there the next time I run it. Is there any way to permanently fix the rep layout on Blueprint objects? (I cannot recreate blueprint classes, they are HUGE).

Best,

I did some further testing: the error only occurs with PIE, not in packaged builds. Also, it appears not only for character but (somewhat randomly) for blueprints that use inheritance. For example, it also happens in all my projectile classes (again, the structure is Actor → Spell (C++) → BP_Projectile → BP_CosmicShards). Still haven’t found a workaround this issue, it is really frustrating because I cannot recompile all those blueprints every time I open the editor, they are too many.

Should I insert call stacks and debug issues, or try to reproduce this on simpler projects? Could it be the problem when switching versions only?

Hey, I’m experiencing this issue as well, however it was not after switching engine versions. Up till recently we had a blueprint-only mulitplayer game, but since we want a dedicated server, we need to add c++ to the project. After doing that i restructured quite a lot inside the project and that was when this crash occured.

We believe it’s related to inheritance when combining blueprints and c++ and I’m currently rolling back to track down possible reasons. I’ll let you know if i find anything useful!

Yes, it has something to do with how C++ and Blueprints interface but, if this helps, the issue was not present in 4.10. I merely switched to 4.11 with the same code, and the issue is there. It could be you did something similiar to mine code when refactoring for C++ support. I hope you have luch reconstructing the issue, it is impossible with my code base unfortunately.

+1. I have the exact same problem, only my setup is a bit different: my classes that inherit from Character are all blueprint classes (no C++ class among them).

+1, Same problem here. With code upgraded from 4.10 to 4.11. I’m trying to replicate a variable in a character BP, and the editor crashes straight away with PIE.

RepLayout.cpp, line 2209 check( Property->PropertyFlags & CPF_Net );

Addendum: After reverting to blueprint only i kept working with it, but now the error has shown up again, this time no c++ or version switching is involved…

Can I provide anything to figure out what the problem is? Unfortunately I dont even know what causes the problem, i just know the blueprint from the VS break when the editor crashes.

+1, I am having the same problem and yes, my code is upgraded from 4.10 to 4.11, it just began to happen yesterday, even though I upgraded it as soon as it launched and I already had raplicated elements.

+1. I’m running into the same problem. Has anyone found a solution to this yet, or know if it’s been addressed in 4.12? I’ve read through the patch notes as best I can, and nothing is really popping out at me.

got same problem after converting to 4.11 to 4.12. additionaly my character_BP child mesh component values reset now. Happens only in editor but not in standalone game. So much bugs in new version.

I can confirm this. But my mesh components are copied on the childs.

+1 the Error Appeard after the Upgrade from 4.12 to 4.13 and only if I am playing in multiple PIE Windows (Number of Players > 1). No crash if I open one instance of PIE nore in the Build version.

I got a workaround by making minor changes to the derived classes so that the Engine realiesed that they have changed and want to recompile them. The result is that I can start the Project with 2 or more (in my case 3) instances of the PIE window. Everything works fine again. But when I close the Engine (using the close Buttons of the Engine itself, saving all changes) and reopen it, the error appears agian.

I tried to duplicate the dreived classes and delete the original once, but tthat did not fix it either.