@akirstein I am concerned about your post because although there are changes a simple export test with old test data shows a difference in the exported JPG but the data is still there! The test was using data created by IMatch that was then input to PL5, according to the file naming this was for PL5.1.2 and exported. I re-exported the data to check what might be happening.
At the same time @Marie had posted in another related post and the final (so far) post from @Marie was PL 5 Keywords Handling: Output Files - #16 by Marie indicating that there have been changes made in the format of the output for hierarchical keys.
The following is a screenshot from PIE that indicates the changes are a reduction in the ‘dc’ fields generated within PL5.2, which I presume is what is being described by @Marie . The dataset is a mixture of JPG and RAW (RW2) images and the _DxPL5 JPGs are from the original tests and the _DxPL5.2 images are what was produced a few minutes ago!
This does not repeat your workflow but the original data was from IMatch into an earlier version of PL5 and then exported in that version and then again just now in PL5.2.0 and shows what has changed.
I will try to repeat your workflow when I have time, to see if I can reproduce any data loss!