I would ask T-Racks (or look on their website) if they have tested and support WaveLab. They will probably tell you that they have only tested and support Cubase and will assume that if Cubase is OK then WaveLab will be OK which is not true.
Have you actually tried “all other DAWs” or do you just mean the main DAWs like Pro Tools, Logic, Cubase etc.?
Surely there are more DAWs than just PT / Nuendo / Logic Pro X / Studio One. If you test Sequoia, Sonic Solutions, DSP Quattro, Triumph, REAPER etc. you could find issues. My point is that the plugin developers often don’t test some of the DAWs with smaller user bases like WaveLab. They only test the main ones.
As for Acustica, I’m not surprised here. Of all the many plugins I have, Acustica is the one time I asked for a refund because I found them to be so bad logistically. Again, I would ask Acustica if they have tested their plugins in WaveLab specifically.