Need some help here
Had some crashes yesterday so x y offset is a bit screw up but that’s not the issue at the moment.
Towards the end of the video, my white toolhead appear to dip down in Z while printing… This is very confusing. Is it possible I have a bad z motor?
Here’s a close up view of the print. Perimeter was fine but then all sudden Z start to drop right around solid infill
missing/deleted image from Google+
Do you have auto bed levelling enabled?
Nope. I managed to avoid auto leveling so my bed is levelled manually through build construction.
I’m thinking perhaps motor idle while the other toolhead on standby might cause the z to drop…
@Step_Cia Have you tried printing on a raft?
Not a big fan of raft. Anyway I think I might have solved it by increasing the current while motor idling during dual printing
Did you borrow the om nom candy as a 2 color test print idea from me? 
@Step_Cia No, I’m not a fan either. I meant it to be a way of seeing if it changed things.
Idle current could be the issue depend of your z construction. If it is ballscrew or belt or very high pitch high quality screw than during the motor idle and work current switch you may loose Z height with rate about 1/4 of full step if your idle current is too low. I had same issue on my cnc but the head wight there was 15 kilo. For the test you can suppress idle current.
Found the culprit. Short bowden tube on right hand had too much pressure and it pushes down the hotend thus Z appear to dip…Fixed and printed nicely.