Suppose you are accused of something that doesn't make sense or shouldn't be placed on you based on jurisdiction, and decide with your retained defense attorney to file a motion to dismiss those charges.
If the government has already offered you a plea offer quite early on, with no jail time/small fine, can they make that offer less favorable just because you filed that motion?
They were annoyed and "mad" that you've bothered to file a motion, so they screw you over with an increased sentence?