RAMWolff

There are several algorithms to convert from 24 to 8 bit colour and they don't all work by using the 256 most popular colours from the original. Hence you can't guarantee that any of the original colours will be present. OTOH, the 8 bit version should at least appear the same as the original, so I'm not sure what's happened here. I'd recommend you export at 24 bits, otherwise double check the conversion options. Maybe the transparency is confusing it.

X's 'Show Printer Colours' actually means 'Show the artwork as it might look if it was sent directly to a professional printer without CMYK compensation'. It's only an approximation (hence the odd colour shift) and it doesn't tell you anything about how your artwork will look when it's printed on a desktop printer or sent to a print bureau who will perform the CMYK conversion. Show Printer Colours is really only useful if you're working with Pantone or other CMYK colours on the page.

Regards - Sean