Vented condensate clean-out

I’ve read somewhere that on heat pump systems, the condensate drain clean-out cap should be removed and left off to prevent negative pressure in the drain line. Is this correct? The argument is that heat pumps (as opposed to traditional HVACs) will pull air across the evaporator coil creating somewhat of a vacuum. Love to hear what you think. I need to be educated.

It would be like a 3/4 in hole in your duct if left off.

Does it matter what configuration the coil and blower is?

I’m not sure. Never seen one that wasn’t under the A coil.

This one is a heat pump with the coil located between the return filter and the fan blower. Air is being pulled across the coils rather than pushed.