Sweating hoses

After the vehicle sat for the winter, I noticed the heater hoses are covered with a sticky shiny coating. It does not wipe off with a dry towel. The radiator hoses do NOT have the gooey coating, only the Gates heater hoses.

I thought maybe there was oil in the cooling system after a recent head gasket/intake gasket change last fall.
I went to look at my stock of new, never used heater hoses....and they have the same gooey coating on them too, not as much as the hoses on the engine, but still gooey none the less. So cannot be only an engine issue.

I"m going to carefully flush the cooling system, and install new hoses...but this does not answer the question why off the shelf hoses are weeping a stick substance.

Any comments or experiences are more than welcome of course.