Very slow LR Classic 11 synchronisation with mobile

[robertł60424484]

After upgrading to LR11 I noticed extremely slow synchronization with LR Mobile.

My workflow is the following:

1. Import photos to LR Classic to synchronized folder (M1 Air).

2. Do the culling on M1 iPad Pro + some initial tweaks

3. Do the final touches back on LR Classic M1 Air.

After working this weekend on LR Mobile I noticed that the changes were not synched back to LR Classic. I tried all the different tricks but the progress was very slow. I could see the changes in Lightroom Web version but not in Classic. The changes in the other direction (LR Classic - Mobile) worked as expected.

Now the changes seem to be synchronized but it took over 2h for just metadata synchronization of <100 photos.

During that time I could not see any issues in the LR Web version, no errors shown there. I account it to the new version (11).

[robertł60424484]

I just run a test.

1. Created an empty collection in LR Classic.

2. On LR Mobile, from the collection which has problems with syncing, I marked all rejected photos and copied them to this new collection.

3. The photos got synchronized, the count was correct BUT only half of the photos have 'rejected' flag (1097 of 2244).

I have not find a way to force synchronization of the star rating/flags. It all looks good in LR Web but does not get synced to LRC. It was working fine before the upgrade.

What's really odd, synchronization LRC -> Cloud works as expected.

I initially reported it as a BUG but it was moved here - I guess LR team does not believe it's a bug!

[robertł60424484]

One another test.

This time I did changes on LR Mobile in small collection, <50 files. It all worked as expected.

So it might be related to the size of my synced collection (over 15k photos) but weird thing remains, that synchronization from LR Classic works just fine.

Any suggestions?