Load V8.5 Song into V15 - Immediate hanging notes on several VInst channels that won't stop!

Loading from 8.5 Pro to 15 Pro, and from the point the song loads a few of my channels suddenly play a constant drone from the synths I have loaded. Doesn’t matter which synths, it’s a very low note, just constantly droning away even under the midi in the regions on that channel. It requires me to send a All channel midi note off to end the drone, but as soon as I go back to the song start, it comes back again. It’s driving me crazy as I only upgraded to V15 yesterday from V8.5. Please can anyone help?

What synth is making the drone?

External hardware or a VST?

If VST, is it vst2 or vst3?

Hi, thanks for replying.

Lush 101, Lush2 and Padshop. Doesn’t seem to matter which synth.