First layer print issues when not using tool head 1
Tool heads have their offsets stored in the printer under settings / tool / tool number / offsets. This enables multi tools to line up with tool head 1. But when not using tool head 1, the stored z offset creates first layer print issues. For example tool head 3 is the only tool being used. It has a stored z offset of .35mm. Tool head 3 does the bed mesh and then applies the .35mm offset to the print. If a tool head is always used by itself the z offset should be set to zero.
Complicating the matter is if 2 heads are used with each other but not tool head 1. For example tool head 3 is the primary and tool head 4 the secondary. Tool head 4 needs to be referenced to tool head 3. For example if tool head 3 has a stored z offset of .35mm and tool head 4 .25mm the new offsets would be 3 and 0 and 4 at -.1mm.
Before making changes you should loosen the nozzles and retighten them using the print bed or other object to apply consistent pressure. Then rerun the tool offset calibration. Check all the z offsets for consistency, hopefully .5 mm or less. Then zero out and reference heads not being used with tool head 1. Yes I reported this and showed test results.
Adjusted and referenced Z
unadjusted
