Makes me less nervous, actually. As RW suggested above, it's more indicative of thermal effects than of impact (you'd only expect one of those). The Shuttle bends A LOT due to thermal effects -- cold on one side, hot on the other.
If they changed the Shuttle attitude to do the tests, different places would become hot from the sunlight, and a change in the bending profile might very well occur. It would almost certainly be accompanied by multiple "ticks" that would be picked up by these sensors. (And I think they're new sensors ... meaning that this could have happened all along, and this is just the first time it was picked up.)