Performance Drop with Lumen/Virtual Shadow Maps moving from 5.0.3 to 5.1?

No project changes, but huge Run-time AND Editor lag (2-8 fps) post update. I can’t pin down the cause.
Happens on multiple maps, indoor with directional lights and outdoor with just a skylight.

  • Running Stat GPU shows the issue being Shadow Depths (100-300)
  • Changing from Virtual Shadow Maps to Shadow Maps helps a bit.å
  • Turning on Texture LODs helped a bit (not sure why it was off)
  • Reducing reflection resolution from 128 to 32 didn’t have any effect
  • Turning on Ray Traced Shadows doesn’t really help.

Still a big issue, and editor is crawling to a standstill. Were there any big settings changes in 5.1 I’m overlooking?