Guitar track presets problem

Hi there, I have Cubase 15 Pro (upgraded from Cubase11). PC Windows 11. When I load a rock guitar track preset it’s clean. That’s all of the rock guitar track presets. Sometimes I’m hearing an unaffected guitar. sometimes the signal is going through the inserts. By sometimes I mean in different sessions on new projects. It looks as though the presets are not loading fully as there is no guitar amplifier (VST amp rack) on any of the rock track presets. I’ve checked the monitor button, Constrain Delay Compensation is off, the track is mono. Any suggestions?