Any idea on why this would be happening? Is the theme setting a session? Maybe the session is expiring or being cleared by their client?
I only have a few people reporting this but it’s odd for sure.
They have the Dark theme selected and it’s fine for 7 days and then reverts to the Light theme (the site default).
For at least one of the people involved it’s happening on their mobile/phone.
Are they applying the theme change to all devices or just for a specific device?
From what they are telling me they are using Discourse from that device, the theme changes, they change it back and then 7 days later on that same device they see it revert back to the default theme. I can ask them about using it on other devices, but isn’t the theme choice set in their profile settings, etc?
Also at least one of the other affected users is seeing this happen on a PC client browser as well.
Are all those users on Apple devices?
By default, a custom theme applies only on the current device, unless you check this box manually:
When that happens the theme preference is saved locally in the device using a cookie.
On Apple devices native browsers, those cookies are removed after 7 days:
Apply theme to all devices, so we save that on the server
Never fail to visit the site for 7 days
on MacOS you can use another browser. Not an option on iOS
on iOS you can install the Discourse PWA with “Add to Homescreen” which bypasses the normal 7 days counter for a different one.
Ahhh… yes that sounds like what is happening then.