Sounds to me like a faulty safety valve. I've seen in some masts there were more than one safety valve, the main cylinder or FFL cylinder has one but also one of the secondary cylinders contains one also.

usually when they stick or get damaged they will cause mast sequencing issues and even some drift.
When you raise the mast up and then lower it the inner channels stay up some (meaning the outer cylinders are not fully lowered) so when it hits the bottom the outer cylinders drift down.

This sound like your symptom?

Just an off the wall thought that came to mind while reading this