I believe this was simply a coincidence - can't imagine what the odds are. But remember what Spock said, "When you eliminate the impossible, whatever remains, however improbable, must be the truth" Always waiting for a chance to use that!
I don't believe your transformers, phased or not, (and they really should be) had anything to do with this - the 153C contactor does not connect to the hot rail or outside rail, it's just a SPDT switch. And if I may quote you, " I ran trains over the outer loop to adjust the 153. All went well." So if the transformer phasing was truly an issue, things would never have run correctly from the get-go.
If it were me, I would just put everything back the way it was and try it again! Your 675 obviously still needs a look-see, and it could just as easily be a bad finger contact to the e-units drum as it could a loose or broken wire, cold solder joint, etc. But troubleshoot it separately, on a simple loop of track. Once you have fixed whatever issue it has, then throw it back on your layout!
George