For me, it goes back to this post where I was seeing issues using these 50uL tips on a STARlet.
I would also have issues picking them up sometimes, where it would give a channel error. I need to go back and track down the error (switching tips was the solution) but essentially it would pick up the tip, give an error that the tip was not picked up, then proceed with the aspirate/dispense instructions but not actually transfer any liquid.