I’m convinced this is got to do with Delay compensation. Whenever the problem occurs on projects the plugins cubase WILL let me load are either its own stock plugins or ones that are low on latency such as UAD Cambridge or Waves Api 2500. These usually WILL load when I’m having the issue but anything like C6 or Waves LMB or UAD Thermionic or anything like API Vision or Neve 1073 or Plate 140 will not load at that point in the project.