Air in pool pump cover

When I turn my ingrounded pool pump on it shoots out air bubbles in the pool for 10 seconds and then ends.   When I look at the pool pump basket there is no air in it.   After a few hours,  maybe 3 or more,  I notice air in the top 1/2 inch under the cover at the pool pump.   The pool is 10 months old and I am now concerned that I have a leak in the underground pipes!   Anyway to tell if the leak is underground or above.   Is the answer to check all connections above ground first or is this issue a non issue?