What can happen is the thermostat is stuck by some debris for a little while and the pressure on the system rises so a slight leak can develop anywhere and then disappear when the thermostat opens again.
But, the flashing led is strange, canīt think of any such connection? Maybe it is visible in the cars memory?

Anyway if the pump is starting to leak it will continue and soon enough you will also be able to hear some noise from it.

If no more coolant disappears and no more puddles under the car, it could have been the thermostat. Check that all hoses are tightened as well.
L.