I have a 1100MX with auto oiler that had similar Z axis oil supply issues. I chased this problem for quite a while before I found a very small leak that was allowing air into the oil line supplying the Z axis. In my case the leak was at the “banjo” fitting on the side of the column. The air leak allowed the oil in the oil supply line to drain down overnight, and the time required to refill the oil supply line and provide lubrication to the Z axis was greater than the recommended oil pump run time.
I added a small pressure gauge to indicate the Z axis oil pressure at the top of the Z axis. See pictures.
