Hey Harry,
I have gone back into the manual and found a remark at the limit switch part of the slb manual. I have no idea if it is still valid or needs updating, but it might be that this is the source of your problem?
The latest post by Chris on auto squaring (needing the 2 y sensors) was Jan this year. It was an early beta version. He even released a -at your own risk- trial in the last post in this thread here:
Please note the pretty clear warning posted on using this u tested feature:
