As I suffer this since I came back to .sg in 2015, had so much frustration which made me quit a ton of times, but metin2 is an addictive bugged monster.
This is the bug:
Pardon my lack of pictures, as I have my Windows system in spanish, I can't upload pictures, but I'll try it to be the most understandable.
For all we know, people with Intel processors don't suffer this bug often, as only does AMD in great part of their processors. Some people do suffer this bug even without AMD products.
The fix is simple:
1º: Open your Task Manager.
2º: Select your window of Metin2 which you wanna manipulate, and right click over it, in that menu click "Go to details"
3º: Right click again over the marked "metin2client.bin", and click "Set affinity" in the menu.
4º: You will get a window with boxes, "<All processors>" is the first and the default option, you should click only one core "CPU 'X', (being 'x', 1, 2, 3, 4, if quadcore) and click "ok".
Once you got a window of metin in one core, if you open other window of metin, you should get it in another core not used, for example I use one window in "CPU 2", and another in "CPU 3".
Do not use other programs which could use the core metin is using, because you could get the bug again. Every time I've done a DT with youtube open, bug appeared.
Don't worry if you think this will damage, as it's not permanent and will not damage anything, is a tweak you do every time you want to do a dt or another run, the bug could appear, but I met it rarely now, and maybe is because I left Chrome open.Please let me know if it works for you, or if you have something to add. I'm sorry if it is not clear, I'll try to make ilustrative pictures. And I hope this helps. Thanks.
Edit: It helps but doesn't prevent the appearing of the bug.