I have created a support script to sync ShotGrid playlists to SyncSketch after a successful delivery to ShotGrid. The call I use is the following from the python api:

shotgun_sync_review_items(...).

While the script works nicely, I have noticed on its deployment, that it is too fast for the ShotGrid transcoder, which is still creating a thumbnail for the ShotGrid Version after my script finishes its work. This results in an annoying behaviour that for 99% of media files synced to SyncSketch have the ShotGrid placeholder thumbnail, as seen in the attachment.

I am currently considering multiple workarounds to solve the issue, be it time delays or thumbnail URL updates.

But honestly the cleanest solution would be adding a new parameter to the API call, e.g. ignore_sg_thumbnail=False. Such a parameter would simply force the sync to not sync thumbnails and for legacy reasons we could default it to False to keep the current behaviour.