Hi Greysmith,
To my experience, it looks like frost damage. The tree is pushing the sap but the sap does not go through to the top of the tree, so it leaks ...
Wait and see - but to me that stem is dead .
I would monitor the roots at that stem and check that they don't rot due to stagnating water. And if they do rot, I would remove the roting material .
Has it dried out since your post ?