If you short a put spread yes. If you short a call spread, you want the opposite. You want the underlying to close below the short strike.
Due to the option having higher value than the diff. between the strike and the underlying price, a phenomenon called "extrinsic value", even though the short strike has not been touched but the price on the spread has already increased so much that it's threatening their profit or has already turned their position into a loss. So in order to minimize their loss or walk away with still some profit left, they choose to close out the spread or just the short position. The underlying does sometimes reverse back later but that's not something that the trader can foresee and the trader doesn't want to deal with a bigger loss from assignment if he/she holds it all the way to the end.
Traders stop-loss or tp early on their trades all the time, doesn't mean that they shouldn't have entered the trade in the first place. Stop-loss or tp early just means that at this moment, the trader doesn't believe the position would be profitable or more profitable anymore. Traders are required to adjust their positions throughout the entire time when trading according to new information. That's what we traders do.

Some traders do hold the position till the end and just choose to deal with the consequence of being assigned and sometimes they are rewarded for their resolve in "standing their ground" sorta speak when the market reverses but you never know. Everything is down to probabilities.