I suggest, as a general rule, having a policy of stopping the walk around when an issue like this is discovered, advise maintenance, and then resume the walk around. It makes it less likely that the issue will get forgotten
Interrupting a pre flight can, and has, been the undoing of flight safety, can point to the loss of a DC-4 and all on board when the aircraft was the main stay of airline operations, our own outfit had an engine cowling come loose in flight and cause damage that took six months to repair, exhaust gases impinging on the airframe changing metal temper was what took time to fix. On both occasions it was interruption to take a phone call that initiated events.