I usually take RAW+JPG shots but this time I went for pure JPGs with Leica Q2. To my surprise LR Classic does not seem to be able to sync these. None of the JPGs are getting synced to cloud (or appear on LR Mobile). They're stuck in LR CLassic with status 'building smart preview for lightroom ecosystem'. I already tried to delete the smart previews and force the sync again - no luck.
In Lightroom Web I can see these photos in 'sync errors' with message 'sync has not finished for file <my jpg file>. Open lightroom on <my laptop name> to continue syncing'. LR Classic is open, no sync errors shown - I am clueless how to fix it. It works fine with RAW files or RAW+JPG combos.