- The tab has been renamed from Sync to Lightroom Sync.
- The Rebuild Sync Data button is no longer visible but rather a hidden easter egg accessible by holding down Opt / Alt.
- Rebuild Sync Data isn't documented. From the user forums, it appears this is a fairly common suggested magic incantation, so documenting it would be worthwhile.
Lightroom Classic 8.4 was released today and contained a fix for this issue. Please update to 8.4 and verify that you are no longer seeing the issue. Thank you!
The incorrect information was corrected, but the hidden easter egg Rebuild Sync Data still isn't documented. It's a common suggestion on the forums, so documenting it would help explain to users what it does.