Hello,
Since we migrated to 11.3, we noticed that very often, when updating webscenes in Scene viewer, the following error message appears after saving it:

Debbugging it, the request:
https://myportal.company.com/geoportal/sharing/rest/content/users/myuser/5dbe9521827f4cb9b57791f40f93e53b/items/c3b4c329aabd42b3907223d29f949ef8/updateThumbnail
returns:
{"error":{"code":500,"messageCode":"CONT_0108","message":"Unable to update thumbnail","details":["Invalid Url"]}}
Even after configured the Portal for ArcGIS logs to DEBUG, I do not get anything about this error.
I can't reproduce it from scratch though: that is to say, creating a webcene and saving it works. Reopening it, updating it, saving it again works as well. It is as if this issue only occurs after a while.
Anyone facing the same issue ?
Thanks,
Nicolas