Yes it is full of strange anomolies. If I upload a RAW file with Canon DPP it has full EXIF data when viewed with DPP. After conversion to TIFF, DPP still shows full info but other programmes have limited data. And after editing with another programme and exporting to a different folder (but still TIFF) all EXIF is lost.
However, if I resave the edited image to the original unedited TIFF file the basic info is still there.
And when shot in JPEG the basic EXIF remains no matter what I do with that file.
When viewed with ACDSee I am able to add more information but it can only be read by that programme.
Like so much of computer technology, software manufacturers use their own formats which aren't compatable with each other. It's a good job they aren't running a railway!