The following sentence's meaning is ambiguous. Provide two explanations that illustrate the different meanings of the sentence: Visiting relatives can be problematic.

Ambiguity is created because the function of the word "visiting" is unclear in the sentence. The intended meaning depends on whether the word "visiting" is being used as a gerund (a verb functioning as a noun) or an adjective.
If "visiting" is meant as a gerund, then it is the act of visiting relatives that is the problem. In this case, "visiting relatives can be problematic" is an observation that the act of visiting one's relatives can create difficulties for the visitor. For example, the relatives might live in a place that is inconvenient to get to or uncomfortable to occupy. It could also refer to the relationship one has with the relatives; perhaps your personalities are incompatible and the visit will be filled with tensions, misunderstandings, or other difficulties that create problems. It could also mean the time spent visiting relatives is time one needs or wants to spend differently.
If "visiting" is meant as an adjective that modifies "relatives," then the problem is the relatives who are visiting. For example, your relatives may impose on you by making inconvenient demands or overstaying their welcome.