Stop in for a cup of coffee

Air gets into the cylinders, so coolant could find its way back. Unless turbo has coolant running through it. Then from turbo?
Not in the HX35, Cummins did use a water cooled turbo but that was only in generator and mining operations. Not in the dodge truck.

I have new theory after thinking on it.

I’d removed the intercooler boots prior to draining the block via the lower radiator hose. I popped radiator hose off and made a mess everywhere. I’m wondering if some coolant didn’t find its way into the intercooler that way.