Maybe because you broke the rule regarding bumping a thread:
[Snip]
There might be some rules that was evade, but these kind of rules (above posted) doesn't trigger for banning an account IMO, unless evading board rules or an obvious plagiarism.
I bet the reason for this is plagiarism, as a project's official account, obviously its good for them to spam/repost their articles to any kind of forum or social sites.