Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet

[JOGARA]

Is your Z axis calibrated correctly, and not gaining/loosing steps?
I'd double check the calibration, then mark the z-shaft, create a program that runs the Z up/down a hundred or so times, and check it's returning to the same mark.

If that reveals nothing, try modelling and machining a simple stepped block, to see if it's a fusion or machine problem.
While machining pay attention to where the mark on the shaft is at a known position, then return to that position at the end to see if anything has moved.

This has only been a problem with the last 2 setups I have ran.
All the ones before executed as expected.

[m_c]

This has only been a problem with the last 2 setups I have ran.
All the ones before executed as expected.

I wouldn't make assumptions!
Are your previous setups still working as expected?

[JOGARA]

My stock in Fusion is the same size as my actual stock. My part is the same height as the stock so no offsets.

I am manually moving the bit down till it touches the surface. It has been more than accurate for what I am doing. Not 0.3mm out though..

I am pretty sure this is a thing in CAD though not the machine or my physical setup of it.

I wouldn't make assumptions!
Are your previous setups still working as expected?

I can test tomorrow.