Recently found an old post that remained unanswered because the cause of the bug and fixing it was unknown.
Basically the bug is about turfs not blinking on the Radar/Map and today I've found the solution/problem which is .NET framework being outdated
or it isn't working properly anymore with SAMP.
I installed this update today and after 4 days of having this bug, it just fixed itself after installing this update through windows.
Cumulative Update for .NET Framework 3.5 and 4.8 for Windows 10 Version 1909 for x64 (KB4552931)
You can find the steps to install/update .NET framework on Google, there are plenty of sources which carefully explain the steps for all windows editions.
Keep this thread alive as some people may still experience this bug and can use this thread as reference to add possible triggers to this bug and to confirm that it's fixed by following the above mentioned method.