ssh linux freebsd keyboard input problem?

Question

linux

Briefly: when entering commands via ssh, spaces and command history are inserted themselves.
More: there are 3 vps
1) Debian Netherlands, ssh on custom port, ufw, wireguard server
2) Russia Debian, default settings, slow (5mb/s) channel
3) Russia FreeBSD, almost default settings
All 3 servers and my computer in total vpn networks through server number 1.
When working with the second and third via ssh, from time to time (in about 30% of connections) there is a problem with keyboard input to the console - sometimes when the cursor moves with the navigation arrows or erasing the backspace, sometimes with any press, the cursor spontaneously starts jumping a few spaces to the right, insert commands from the input history (sometimes several directly per line). At the same time, there are no lag-freezes, everything is instantaneous, ctrl + c also works.
There seems to be no problem in my computer - I tried it with different, with different terminal emulators.
Here is something similar https://forums.freebsd.org/threads/input-problem-o...
But still I suspect that it may be due to the Internet, but why then there are no visible freezes, and it is guaranteed was a fast vps server too...?
I tried to connect inside the vpn, and to the external ip - there is no difference.