Here is my scenario to reproduce
1) upload of a Jpeg with Title and Description IPTC metadata
2) change the IPTC Title with a picture editor the same raw editor (lightroom, DXO, etc)
3) upload the new edited file in your X3 panel, the file is added with the number "1" after the filename because it already exists. So now there are 2 files :
- Picture_name.jpg (PIX1)
and
- Picture_name1.jpg (PIX2)
4) In the gallery, no problem, there are now 2 pictures that are of course the same but with different IPTC data
5) I delete the PIX1 and I rename the PIX2 with the PIX1 name so now I only get Picture_name.jpg in my gallery file list.
6) and now I check and X3 still displays the IPTC from the PIX1 instead of the PIX2. It seems X3 saved in memory the IPTC data and could restored it by matching the filename from the first file, that has been deleted but not the metadata !!!
7) and now, It's magical, If I rename PIX2 with anything than the first picture name, included PIX2 filename, I can get the right IPTC data of PIX2
So strange to find and verify this bug, at first I thought about an error during the raw process or upload with X3
For sure I tried to clean cache for Image and Page but nothing more