Auto-marking a single fixture

no. if it happens a lot during a show i would suggest using two cuelists, one that gets automarked and the other that doesn't (i.e. disable automark for all cues). you can then have the console execute the two cuelists simultaneously (Cue 1/ Execute Cue 2/). to make it simpler to record the right channels into the right cuelist you could use cuelist partitions

Just a thought, is the intensity parameter not being used for anything on the winch and/or could it be moved to another parameter, to free up the intensity parameter.

If so you could then set intensity up as a dummy parameter and set it at 100% for the whole show and then the auto mark would be defeated for that fixture.

Thank you very much, in my case this will actually work!

Another way to do this would be to put the channels you don't want to automark in a Q part. You can then disable automark for the part Cue.