@marceltyty1, would you be open to updating to our latest release (v5.15) to see if the issue persists? Do you see any error messages in Mattermost logs when this issue occurs?
Just a quick follow up on the issue you reported. May I know if you have attempted to upgrade to the latest 5.16 as suggested by @amy.blais that just got released about 2 days ago or maybe even install a fresh instance to see if you are still facing the same issue with the profile pictures, team icon, and the attachments?
If not, any chance attaching the mattermost.log so we can troubleshoot this further?
Can you also provide more context on this? What folder were you trying to create and what error are you getting?