PowerPoint Brand Images: folders appear as tabs, but images only show under “All”

Hi there SanderReijn​ as a fan of metadata, I wonder what would happen if you upload an image directly (without folder) and add metadata to it, instead of folders. Maybe just like most AI, PowerPoint has trouble reading the importance of folderstructures? 
An other option to try is maybe upload an entire new ImageDocumentLibrary with a single folder and wait 24-48 hours to rule out latency (though I don't suspect that to be the problem). 
But yeah, as stated by oliver as well... a support ticket would be a great go-to as well and with your problem-statement you've already have a very clear en reproducable scenario description for them 😀