The frozen frame from Viewport 4 “jumps” to Viewport 1 at a random moment and remains there until Switchboard is restarted.

Hello everyone! I encountered a problem when recompiling a project from version 5.3 to 5.6 of the engine, namely a strange bug with the frame “jumping” from the fourth viewport to the first. The project is entirely based on blueprints, with C++ code only in custom plugins.

Some information about the NDC configuration:

1 cluster
1 host
1 local node
4 viewports arranged in a row

  • resolution of one viewport is 1920x1080
  • together they form a resolution of 7680x1080

The bug occurs at random moments, I have attached a screenshot and circled the frozen frame in red. As you can see, the active viewport is in front of this frozen frame. Because of this, the projection on our simulator breaks and artifacts from this frame appear (I won’t go into details. NDA).

Technically, I don’t even understand how it is possible for a frame from a completely different viewport to jump to another. And always from the fourth to the first.

I would like to get a solution from knowledgeable people, even if it’s just a workaround, like resetting the video buffer or something like that, to remove this frame from the rendering.

I’ll add that after this problem was discovered, I deleted the NDC configurations from the project and level and recreated them, thinking that would solve the problem, but it didn’t.