Hi,
Examples attached:
"Original PDF and as opened in Affinity Designer 1.PDF" is as the original CAD export and opens as expected in Affinity Designer 1
"Same file as opened in Affinity Designer 2.pdf" - same image as above opened and exported out from Affinity Designer 2. It is mangled on screen and as exported. Red lines and red hatched square have changed position in the element stack order hiding them.
Affinity Designer 2.3.0 Mac OSX10.15.7
Original PDF and as opened in Affinity Designer 1.pdf
Same file as opened in Affinity Designer 2.pdf