Solo queing with the "Fill Teammates" box selected.

@Bigh0pI am assuming that the problem is with the button, sometimes I get this bug where I hit mute teammates but I am unable to mute them so I am assuming even though the box is checked it may not be working which is why you are being queued solo

https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/

See if this fixes the problem, it usually fixes things for me when buttons/settings are not working right in game

I have been put in UNREQUESTED solo mode at least 20 times.  Three times in a row just now.

YES.  At least 20 times now.  The last 3 times I tried to play duos. (Apex Legends Season 8 via STEAM)

It's been like over a month now and this issue still isn't fixed. Insane.

The reason I think the problem isn't the button is that it takes like no time to enter a game, even if you don't get teammates. When the no fill update came out, it said that there can only be 6 people in the game which are solo queing meaning it takes way longer to get into a game. I'm pretty sure it isn't the button.