After dragging a cube (was happening with my own static mesh objects too) onto the scene. I used the Blueprint/Add Script button (as shown in image 1) to create a Cube_Blueprint. I changed the settings of the Cube_Blueprint to Replicates (as shown in image 2). I went into the Level Blueprint (happens from any blueprint from what I have seen) and set it to On Begin Play, spawn actor (as shown in image 3).
If I press play, with just 1 player, it works fine. But if I add a second player. On play, the client (not the server) fails to load, and Unreal crashes. I also tested this where I didn’t set the blueprint to replicates, and instead set it to replicate when I pressed a key during play. This also caused the engine to crash.
I found that if the object I am setting to replicate is already in the scene, it won’t crash, only for objects that are spawned.
If I create the blueprint not using that button, and instead, right click, create blueprint, and manually set the staticmeshcomponent to the Cube mesh it all works perfectly fine. It only seems to be an issue when using that button.
Hopefully this is enough info for you guys to reproduce this and fix it (if you don’t already know about it and have fixed it for 4.8, but I couldn’t find any info on it when I searched for the problem)