Yes, this could very likely be a problem, and the future buyer's will have to know, because you will have to disclose it to them as a material fact. Failure to disclose this to future buyer's could cause liablitly on your part to correct the problem.

How did this problem come to your attention? Did you have a survey done, or did the seller disclose it to you at closing?

Yes, this could be a problem when you go to sell your home. But not necessarily. If the person you sell it to orders a survey, their closing attorney or title company will surely bring this to their attention and it could cause them to back out of the deal. Especially if the contract is contingent upon a survey. If they don't order a survey then they won't know so it shouldn't matter.

Easements/encroachments are extremely difficult to have fixed. You will have to call a local real estate attorney and have them look into this. If its a utility easement, basically your city will have the right to come in and do any kind of work that needs to be done where the utility line runs. If your house runs on the corner of the utility easement, they don't have to fix anything on your home in the event they need to access where your house crosses that path. Talk to whoever told you this and dig a little deeper. Or talk to your real estate attorney to find out what type of easement/enroachmenth this is.