Yes, I suppose there would be enough difference between the concentrated perpedicular wash from a Harrier and the more tangential, transitory wash from a departing or arriving airliner. BTW, the wash is pretty direct with the aircraft pitches upward to take off, or when it deploys its thrust reversers, but since it's moving across the surface at 150 knots or more, I doubt the effect is significant. And since the Harrier would only heat a certain small area, there's the problem of a thermal gradient and expansion ratios. It might crack when it cools.

Put another way, runways may be temperature-hardy, but they're also very expensive. If there were the slightest chance it would crack, I'd have the Harrier land on the grass.