Illustrator not saving transparency in PDFs??

I have always been able to save from Illustrator to PDF 1.4 or later and the transparency is retained on PNGs and on vectors where the transparency is reduced. Over the last few days all PDFs presets (except 1.3 with Advanced switched to High Resolution) are not doing this?

Am I missing something? Always worked without even thinking about it, now every transparency is printing with a ghost box around it? And vectors with lowered transparency values are printing as 100%. STUMPED!

Have tried everything I can think of, but only the PDF 1.3 setting removes the boxes and prints transparency currently.

Is this an issue with the latest Illustrator update? Any one any ideas?
thanks.