Coolant out of overflow tube

[Penland]

Last year I replaced my coolant reservoir, tried bleeding it (nose down, cap off etc) and kept losing coolant, replaced the cap with the new version. Engine temps were normal.
Put it away for the winter frustrated. Now that I have time to work on it and it’s warming up outside, I took the cover off the bottom to see where it was coming from.

It is coming out of the overflow tube, when I have the cap off it stops dripping.
Cap on and relief valve open it drips as well.
Any ideas? I drained the oil to see if there was water, and there was nothing.
Do I have a trapped air bubble?
Suspect a cracked cylinder wall?