Brownish red bark on my siberian elm

[Elmnewbie]

So I have a roughly 4 year old siberian elm. I cut it way back at the beginning of this year and I noticed a section of bark towards the top of my cut, it's a split trunk and the trunk I'm question was not swing so well. I cut off the bad part and the tree took off. But it has come back again. Is it a fungus infection? How do I treat this? The bark in that area is very soft.

 

[Mike Westervelt]

It's dying back from the chop, when was it cut?

 

[Elmnewbie]

So interestingly enough the first time I cutt, it had that same browning of the bark but it wasn't from where the cutt started. It was a few inches down. It's also only on that side of the trunk. Not all the way around which is what you'd expect from it dying back. I cutt it again below where it was affected and it just started up again. But only on that one side.