We were farming in Old Orsinium to get some rubedo leather, and after a few hours we decided to start crafting ourselves some gear. I traded my leather to him with no issues whatsoever, then he crafted a piece of armor for me. When he tried to trade it to me he wasn't able to trade me. He also tried to talk in PM's and zone chat but it wasn't working. He can't access his guild bank/guild store and also can't use guild traders, and when we asked about it in zone chat he was told that he was apparently social banned even though he hasn't said anything for 24+ hours, and he also has only done a single trade - there's no reason whatsoever for him to be social banned.
Can a developer please explain what's going on and let us know if there's a fix? No, this is not an add-on issue... we've tried it. No this is not an issue with corrupted game files, we've tried repairing the game. Yes, we've restarted the game. This has to be an account-based issue.