2015 Chevy Silverado AC Issue

I have a strange problem, well strange to me. My AC was having a few of issues that I fixed, compressor clutch replaced, condenser replaced, charged and working fine until it's above about 70 outside. That isn't the weird part, once the engine gets hot and I drive for a while or sit in traffic it will start working and cooling perfectly. There is nothing consistent about when it turns on that I can tell. Any ideas?