cracking bark

Hoping I can get a few pairs of extra eyes on what I thought was just normal bark cracking/peeling for one of my elms. The more it progressesn, the more I start to doubt it's normal and all is well. The tree is very healthy otherwise. Thanks in advance!

I thought the sickly leaves could be handled by better soil and fertilizer, but then I took a closer look at the bark. Ive been aware of something going on there for a while but thought it might be a weird thing arakawa does when forming rough bark. The discolored area is spreading and now...