I would get a new T and some crimp rings, rent or borrow the crimper, and replace that one. If there is enough slack to cut off the connector and crimp on to the uncrimped PEX, that would be best. If you can't, cut the crimp rings off with a Dremel tool without cutting the PEX (yeah, right) clean out the inside with a rolled up rag or bottle brush and crimp on the new T. You might check your water pressure to see that it is only around 50 pounds. If it is above that check / replace the pressure reducing valve if city water or your pump shut off switch. Our city water pressure can be as high as 200 pounds.
My local Home De Pot has crimpers for rent, or for sale.
I have seen push on fittings that are supposed to work on copper or PEX. I'm skeptical, maybe someone here has experience with them.
While you are down there crawling around like a snake, check all the other ones you can see. If most of them are leaking you may have a recall, or sue somebody situation.
If the ones you can see are leaking, the ones in the walls are probably leaking.
Hopefully you have just one Friday-going-home-time connection.
Paul