I do tests for you, in PL8.8 and PL9.0. I found no issues with 16:9 cropping, works fine.
Crops all 16:9 setup. I do multiple, with same crop size in different places in the photo, and also different widths, etc.
I export to Tiff, Jpg original sizes, and also test resized Jpg exports., and on ‘original size’ crop, different places, and different width crops
A put results to table.
As its already discussed 16:9 floating, so in some cases its rounded UP (to avoid black lines or whatever in the destination display, etc.)
I highlight this case.
So, an can say, crop to 16:9 its just works.
I like to note, photo not touched at all (no geometry corrections, etc.)