(previous answer on Safari wasn't saved shorter one below) 😡
Sorry to read, I didn't saw other reports with such issue, it something on your hand I guess.
Of course, you flushed cookies and tried on incognito new browser window. ;-)
Install a clean Tiki 21.6 check if you have the same issue.
If you new install works, compare settings between the 2 Tikis and find what is causing the issue. See this tutorial : https://youtu.be/y5H5haNFCWI