New rebuilt automatic transmisssion still popping out of third gear

What is your question?

1992 Geo Metro Convertible had transmission replaced with rebuilt automatic transmission but did not fix third gear still popping out of gear. Does EGR valve factor in? No noise or leak detected.

What makes this problem better or worse?

Worse when engine is warmed uo

How long has your 1992 Geo Metro had this problem?

Months