I am admin of community.humanetech.com and just changed my profile picture from default to an uploaded jpeg image. It seemed to work fine, but when I went to the main page there were no changes and all topics were shown as unread. What happened was that my account had changed and was now named ‘anonymous10’. I had no access to my real account anymore (which was unchanged).
So I logged out, logged in again, and there was no change to the profile picture. So I did the same action again. My previously uploaded photo was still present, and after just changing the option to this setting and pressing ‘Save’ everything worked fine (no cache refresh needed as well).
But I thought I’ll mention it anyway.
I am using FF 60.0 on Ubuntu 16.04