Forum theme keeps reverting to light

I’ve had a few instances now where my preference for the forum theme has reverted back to ‘light’. I normally use the dark theme. This doesn’t seem to be browser cookie related, as when this occurs I do not get logged out or anything.

It’s pretty simple to flip the theme back, just curious what’s causing this to happen.

I noticed the same thing. I just assumed I was doing something to cause it.