What are these "Light flashes" in Eevee .mov render

[SidewaysUpJoe (Joe)]

I keep for getting to try this, but maybe it will help.

Giant white block artifact in eevee render

It worked! Not sure if it was the volume pixel size or the bloom. I’ll turn the pixel size back down and see if it still works. Edit: after some more experimenting, it’s definitely the volume tile size. I changed it back to two pixels and the artifacts came back, but if I set it to four pixels they go away.