Warmane movement speed bugs on character

I play WoW WoTLK on Warmane Lordaeron, and after I don't know how much time, my character started slowing down and got buggy. I tried to play on other characters and it is the same problem. I reinstalled WoW, tried both versions of WoTLK and it's not working. I tried to play on another account, still same. I updated all drivers and it's still not working. I don't think problem is in my pc, because my pc is not too bad. This is my pc specs:

Processor: AMD Athlon X4 750K 3.4 GHz
Graphics card: AMD Radeon RX560 4 GB Video Memory
RAM Memory: 8 GB

Here is what the problem is in-game: https://youtu.be/Mi0LPwoN53E
https://youtu.be/r_sYI46LBfU

What is exactly problem? Problem is when I start walking with or without mount and try to move camera, my character gets slower and gets buggy, as you can see on video, but when I click spacebar it gets back to normal. This happens everytime I want to move camera. Can someone help me?

1. Disable all of your addons
2. menu > key bindings > under "Movement keys" there is "Toggle run/walk". Unbind this key

I tried, still not working. Do you have more ideas how to fix this?

Try another keyboard