I’ve noticed with multiple screens on MacOS 10.15 or 11.x.x, that sometimes, if you open a meter (for the workspace), and drag it to another monitor, then click/hold it to slowly adjust it’s location, sometimes a plugin or other meters can ghost (become transparent) and never return unless you close and open Wavelab. It could be that Wavelab is trying to display the Workspace organization/snap tool, but it doesn’t appear on a second screen. I hope that makes sense.
Sometimes, too, the saved Workspace might “forget” the settings if something about the second monitor changes.