Attacks not working on enemies

[Tortellini]

Client version: Ver. 556
Time: 10-11:30pm EST GMT-5
Character name: Promptus
Character level: 93
Class: Tempest
Location: All Dungeons/Battle Black Dragon Nest
Frequency of error: All the time on this character (Does not occur on other characters)

Description:
1. - The last thing I was doing before the bug occurred was farming the Battle Black Dragon Nest dungeon in Arendel for enhancement plates and guild experience.
- Each run took about 25 seconds since I could kill it fairly fast and I did it at least 10-20 times in a row if i remember correctly.
- All of a sudden my attacks stopped working.

What I have tried:
- Restarting the game.
- Restarting my computer
- Reinstalling the game
None have worked.

Expected result: Attacks and skills damage enemies.
Actual result: They don't damage enemies.
Temporary Solution (work-around): No solution found.

Proof: https://www.youtube.com/watch?v=XKNEhO4TveI
- Video shows me going to Battle Black Dragon Nest and dealing no damage/attacks not hitting. Also going to another dungeon and attacks not hitting.

edit: I searched around and apparently this is an issue that's been around for a while?

[Tortellini]

Well, somehow the problem fixed itself this morning. Logged on and went to a dungeon and my attacks were working again.

[Tortellini]

Problem came back again. Is it because I'm completing the dungeon too fast and doing it too many times? It only takes a couple of seconds to kill the Black Dragon and that's all there is to it. : (

Gonna probably stop farming that one then since I guess the system is flagging me or something.

Well if a GM or whoever can fix this I'd appreciate it.