[CLIENT] The ms values displaying are not accurate

When in game, it is obvious that I'm lagging (experiencing delays of usual 100 to 1000+ms), but in the top-right corner a wrong value is shown (usually between 40 and 50ms, and it's not frozen - it's changing just as it would if it actually was normal). The same value (40-50ms) comes up in chat when I use -Ctrl + right click- on that number (the smart ping).

I've first seen this bug three days ago and have been dealing with it in almost every game I've played since then (Patches 7.22 and 7.23). All of the games that I played in that period were Ascension and ARAM games.

It looks like some kind of a visual bug, but it might be a server problem as well, since the lags have been happening more frequently than before, even when there is no obvious reason for them (downloading big files from the Internet, other devices using the Wi-Fi, etc).

Also sorry if the tag in the title is misleading and if my English isn't really good.

Edit: I have talked to other players and some of them said they have the same problem. And I didn't mention it is happening on the EUNE server.