Thumbnails not displaying in Lightroom cc for images synced from LR Classic

[Kenneth_Poole]

i have a problem with some thumbnails not displaying in LR CC on my iPad (iOS v11). See attached screenshot. The full size images do display, so it’s an inconvenient, rather than a serious problem.

Has anyone else experienced this, and does anyone have a solution? Thank you.

[johanv19432130]

Same problem, but on my windows PC .. On mac no problem.