Yes, this is a concern with some older inverter designs. They use phase-locked loops which are meant to lock to the grid frequency but if you and your neighbours on the feeder are generating and consuming a roughly equal amount of energy and the feeder loses its connection to the wider grid, the loops can lock to each other and form a stable island. How long this would last in practice is not really known, it would probably be rare for it to happen at all and even rarer to stay stable for more than a few minutes but it has been demonstrated so it could have become an issue. Newer inverter have specific anti-islanding protection to detect situations like this and disconnect if it happens.

(the specific case of very little consumption but panels and inverters going full tilt doesn't work as this would lead to the frequency rapidly increasing, exceeding inverter set points and the local grid collapsing with all the inverter tripping off. The danger scenario is closely matched load and generation, like a real grid)