I have a fresh install, latest Pods (and I just double checked by diff), creating or importing templates. When I update the template, it reverts brackets into their lesser than/greater than entity codes (and funnily enough, if I save it again, it turns the ampersands into the amp code, on and on and on...).
I made a screenshot showing the reversion.
I've turned off all plugins, and cleared the cache in Pods, as well as for WPEngine, and I've tested in Firefox and Chromium (with cleared caches as well). I found issue #2207, but I am not have the same issue as that (my template box is showing). Debug info is up as a paste.
I've checked it against other instances of CodeMirror, such as with the Code Snippets plugin, and it works correctly. I've also checked, and there isn't a second instance of CodeMirror being loaded on the template pages.
I am stumped. What else can I check?