Cura and TAZ acting strange ???

We where trying to print a large, assembly jig for a carburetor and loaded into Cura V.2.6.63 on our TAZ6 with the areostruder , which has been working fine up till now, and it may still be.
This is the first layer view in Cura :

Every thing looks normal, note the rear of the bed ( top of the picture ) I is rounded and shows a uniform brim and support base.

We sent to the SD and started the 20hr print. Watching the first layer as it printed it looked like it was failing because the rear of the print was getting changed and sort of smushed ie:

Note the top of the picture does not look like Cura on the bed it looks like an oval.
We let it go and copied the gcode into Simplify 3d that allows you to visualize gcode files. In S3D every thing looked fine. We let it run to see what would happen after it got higher in the Z and It appears to have printed normally even with the strange start

. On the bottom it does show the abnormal first layer.
Has anyone seen this behavior? And what is the cause, the printer?

Thanks Larry