Izotope plugin UIs sluggish after Cubase 10.5.2 update

After updating to Cubase 10.5.2, the user interface for Izotope plugins have been sluggish. For example, I click the preset button to load a preset, and it takes 5 to 10 seconds to respond. Same with moving a fader, et cetera, et cetera. Izotope plugins were fine running Cubase 10.5.12, and plugins from all other companies are fine in 10.5.2…even more system resource demanding plugins. An Izotope plugin as the only plugin in a project is slow, but a boat load of other makers’ plugins loaded at once runs fine. I don’t know if the problem is with Cubase or Izotope, so I’m cross posting to Izotope customer support. Any thoughts?