Rank Decay

Just received a notification on the client stating ' You will start to lose LP due to inactivity ' and that I have 6 days to play before this happens to stop it. Now, I went straight to solo queue currently Diamond 5 won a match and just took a break. Came back after my break and I got the same message again. I would assume the decay is talking about Flex 5v5 since Im Plat1 in that mode and haven't played it in a hot minute. Need help figuring this out. Thank you.