Rapid Rating gone back to provisional?

I played 15 rated games in Rapid and got a proper rating of 1451. I prefer just playing casual chess so I haven't played rated games for a few months. I notice today that my rating has now gone back to provisional. Why is this? I have friends who haven't played for over 6 months but their ratings haven't gone back to provisional?

Can you give an example profile for comparison?

Jay_twitch (for example) hasn't played Rapid chess for 4 months, but his Rapid rating has remained at 1803.

I assume that if you don't play your rating remains fixed. Is this correct?

Lichess must monitor casual games and change ratings based on your performance in these games. I didn't
think casual games altered your rating since they are often played to experiment with new openings etc. (which is why they are called Casual)

inactivity increases RD in Glicko algorith. Ans provvosional rating just indicates that RD is oversome threshold- probably 100. So it just incator that confidence on this rating is not at thesamelevel.

It looks like you are close to a non-provisional rating though!

The RD (rating deviation) is at 113,93 - and needs to be lower than 110 in order to be non-provisional.

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OK, thanks everyone. All very confusing, but I take it you lose your rating if you haven't played rated games in a while.

You don't lose rating, your RD increases over time if you don't play games in that category and your rating becomes provisional once RD is over 110. Play games and your RD will lower below that threshold and your rating will no longer be provisional.

What #7 says is correct. And if it looks inconsistent with your friends who also haven't played for long, that can be for two reasons: either it was a while ago (increasing RD over time has been implemented on Lichess recently, it hasn't always been like that - but the rating system is supposed to work this way), or your friends' RD did get increased but not enough to go provisional.

Thanks for the clarification everyone.