I just encountered a weird thing. My website complains with just TWO out of many photos I posted (JPG from LR), that it can't read the EXIF data. Looking with IrfanView, there are no EXIF data in these two (they got exported in one batch with all the others). I noticed that these two photos are heavily transformed (Vertical -65), whereas all the others, that got some transformation (not all but quite some) don't have such high values and got exported with their EXIF. So. I played around with the vertical value and found out, that the EXIF data gets exported up to the value -39 and from -40 on it's missing. Reproducible.