Webpage uploader doesn't cash images

I using latest Firefox on Windows 10. Previous, when i upload photos and suddenly close browser or mapillary uploader page, after reopen uploader and continue sequence, i don’t have to upload photos, that already been upload. But now, if i cancel uploading process by closing browser, i have to upload all photos from sequence again. Is there any changes to webpage uploader or it’s my browser issue?

This never worked for me (Firefox/Chrome on Debian). The GUI never provided any hint that it was going to skip reuploading some files, and the few times I tried it seemed to reupload everything. So I have always had to cancel + restart.

Suddenly, image caching is work again for me, and i change nothing in my browser, so i assume it was some maintenance on the server.