You can only use profiling tools (or debugging) to find out about it. I don’t think it’s related to the rendering bug discussed in this thread, but of course it’s still annoying and relevant.
What I can tell you, I regularly hit random ensures when disconnecting nodes, mostly by dragging the node and dropping the wire to disconnect it (I know alt-click works, but muscle memory, plus alt key is on my right keyboard half). Hitting ensures sometimes leads to a small lag.
Sorry I can’t help you more, and good luck finding the issue 