Heated Bed Levelling: Right extruder could hit left extruder?

[evilC]

Please forgive the vagueness of this issue...
On the first day that I got the printer, I saw the right extruder hit the left extruder. I forget exactly what the scenario was when I saw it, but I saw something happen today and I think I may know a scenario where this could happen.

I had just finished a print using Octoprint which used the left extruder only. The last position that the left extruder was in during the job was near the left edge of the bed.
The print finished and both extruders parked.
I then disconnected Octoprint, and via the UI on the printer, selected Heated Bed Levelling
After warming up the extruders, the left nozzle un-parked to it's usual "cleaning" spot (So the nozzle was just to the right of the silicone pad), but then the right extruder whizzed across at a very high speed to about the point where the left extruder had finished the previous job at. After doing so, it then moved to the right to the normal cleaning spot, just to the left of the silicone pad.
My theory is that when I saw the collision in the past, what had maybe happened was that the left extruder had finished the job at the very left edge of the print surface, so when the right extruder did this "whiz to where the left extruder was last" thing, it smacked into the left extruder.

Again, please forgive the vagueness of this issue - normally I would try and do some investigation and attempt to repro the scenario, but obviously I don't want to repro one extruder smashing into another :P

[747lulu747]

Hi evilC, thank for your proposal.

We have tried to reproduce the phenomenon but without success.
We will continue to pay attention to this issue. Please let us know when you encouter such problem.