Vacancy clauses apply to owners too
Most homeowners forms restrict or exclude certain perils once a dwelling has been unoccupied for a stated number of consecutive days, commonly sixty. Vandalism, glass breakage and water damage are usually first to go. A household that leaves in May and returns in October has crossed that line without anyone mentioning it.
Water is what actually happens
The classic seasonal loss is a supply line or water heater failing in an empty house and running for weeks. It is also the loss most likely to sit inside a vacancy exclusion, which is the worst possible combination. Shutting the water off at the main is the single most effective thing an absent owner can do.
There are forms written for this
Seasonal and secondary residence policies exist, and some carriers simply endorse the standard form. Either way it has to be arranged deliberately, because the default policy assumes someone is home.