How to keep order of pictures after saving

I have a large document (150+ pages) in LO Writer with a large amount of figures. Each figure is in a box containing the label and the image(s). Some of those images within a box are stacked and I have put them in a certain order (so one in front of the other). All this works until I save - close - and reopen. After reopening the order is gone and I have to restart.

I have tried with 5.0.5 and 5.1.1 - both the same.

File format being used?

Normal odt

I had a similar problem when stacking images. I solved it anchoring images to the same place. For example, anchoring images to the frame.