Oh, god, yes. I've worked with multiple enterprise-oriented software companies whose founders hustled to make early sales at any cost, and then ended up creating massive long-term costs that far outweighed the value of the initial sales. "Poison chalice" customers are common in the enterprise space -- they look great up front, manage to ameliorate your burn rate, and then you end up mortgaging the future of your company to support a small number of contracts. It's incredibly hard to turn down those contracts, though, especially as they often come in as relationship sales, and because the companies in question rarely staff up sales at the beginning.
I consider this a good example of why founders need to onboard professional sales as soon as reasonably possible; it's a whole lot easier to turn down those poor-fit sales when you've got an active funnel, and it's very hard to build that funnel when your entire company is trying to keep those poor-fit contracts happy.