I finally got to spend a little time at the range recently. Came to the conclusion I should shoot a lighter pistol for a while, so I put a 4" bull barrel on the frame I've been using lately and went out and sighted in last night. Durinig the range session, there were a few instances of the hammer following the slide forward. So when I got home it received the best cleaning I could give it without removing the parts from the frame. Had the barrel, grips and slide off. I removed the slide's internals and scrubbed and hosed everything with contact cleaner.
I verified the sear spring wasn't in the flipped position and didn't see anything that looked out of place. After work tonight - and prior to the match - I figured as insurance I'd do a little adjusting to the disconnector just in case the top was worn enough to prevent it from "disconnecting".
Put her back together and headed for the match. Got half way through the match and had the hammer follow the slide twice in two mags.
I violated one of my own rules to never trust a pistol that has been worked on without a good session for it to prove itself. I had convinced myself the problem was properly diagnosed and resolved.
There's a price to pay for being cocky
EDIT TO ADD: When I truly solve it I'll post what I found.