I smell antifreeze in the cab at startup of defrost. No leakage evident in cab. No apparent effect on heating/defrost capacity. What's going on?

What is your question?

heater seems to be pushing anitfreeze odor into cab; haven't tried AC.

What makes this problem better or worse?

Its worse at startup; slight film on inside of windshield; stopleak has made some noticeable difference. If vehicle sits unused for a few days the odor is present again at startup.

How long has your 2014 Chevrolet Suburban 1500 had this problem?

2-3 months