You’ve most likely discovered the ‘Fussy-ness’ of Fritzing and making Parts & PCB’s…
It does take a good bit of working with to understand the workarounds to getting what you want. But, you can get there.
( An aside comment) Personally, after ‘getting there’ with Inkscape, I discovered easier-to-use drawing apps and couldn’t delete Inkscape from machine fast enough!
But, ALL drawing apps I’ve used have Quirks requiring time to figure out… Not a perfect world.
Regarding your last post/issue - consider these comments:
• Correct Layer Order
• Correctly ‘Differenced’ or ‘Subtracted’ features
• Correctly made Paths
• Correctly ‘Scaled’ features (depends on DPI export and design values of feature size)
• The big Red rectangle results from incorrect aspects of the above (been there a million times with similar results). That, in addition to a few other ‘head-scratching’ quirks.
Never saw Big-Red for “PCB” but have seen it many times for ‘Parts’ and the Part’s PCB svg. Attending to the above corrected it.
Can’t make cutouts in Parts only can do it in PCB (not the PCB of a Part)