Two wrongs don't make a right

The administration of the office building where I work isn't exactly the most grammatically correct. Many, many, many... many time, they've posted signs that have shady grammar, not to mention the usual spelling and sentence construction errors.

Case in point, from today:

Really? This sentence is wrong in at least 2 ways:

It's either "will resume" or "will be resuming."

Proofreader, please.