I have used the follow my flight mode before but my last 3-4 flights about 1,5 month it doesn't workbecause it says it has poor GPS signal but at the same time it has 18-20 satellites.
I have all up to date and calibrated and reinstalled soft on drone.
Do somebody have same problem?

Have the exact same problem, why ????

Are you sure it doesn't say "Device GPS signal weak"?
That usually means that your mobile phone, it's gonna follow your phone. Go check if your phone has proper GPS reception.

It occurs when you want your "Home point: me"

It isn't your GPS signal from your aircraft, it is your mobile device. Probably an iPhone 7.
There are many topics about this issue. But it seems that no one knows exactly if it is an iPhone 7 or an DJI problem.
I know for sure that my iPhone 7 has this problem. Strange thing is that when I look after a flight in the flight list and look at a random flight, the whole flight has a 'blue' dot, where my controller is. In real flight the dot is in red. That means that the aircraft cannot find your remote to follow.
I hope(d) that new firmware would solve this.

I flew Saturday and while Go 4 reported strong GPS signal when I activated Follow Me, it didn't actually follow me. iPhone 7 on AT&T, all latest firmware/app and iOS versions. On another thread, a claim has been made that DJI will remove support for this feature on certain phones, but I haven't seen any movement on this.

Yesterday I got good gps signal and I was abel to turn follow me on but drone didn't follow my it just stays in place when i walked away.