After posting I found this topic Snapmaker Artisan Dual Extruder Nozzle drool which seems to be essentially the same issue.
The two suggestions there are:
- Increase temperature rather than reduce it.
I’m slightly confused as to why this helps. I am printing PLA and have the same issues at 200°C and 220°C. I can try going up further but I am expecting that to cause other issues.
- Remove the silicone covers
This is interesting because I also noted that different versions of the slicer did or did not set the unused end to cool as it alternates. I think it seems fair that it does not cool because it slows things down, is a lot of cycles, and I think the oozing would occur before it got cool enough? But perhaps others with more experience have something to share.
Thanks