'99 OBS CC SWB Brake Issue

[SCOTI]

Finished up a brake rebuild on my '99 OBS truck:
*Rotors
*Calipers
*Pads
*Wheel bearings/seals
*Hoses
*Master Cylinder
*Rear wheel cylinders
*Rear shoes
*Drums

Well there still seems to be some post work diag effort needed. I bled all 4 corners per usual. Did 3-rounds after purging all initial air from the lines first. Bench bled the new master within the last week & kept fluid in it until install.

Sprayed everything down connection wise w/some brake clean so I would have dry surfaces when leak checking. Took a couple laps around the neighborhood. Stopped as expected. Re-checked for leaks & found 1 area where there was moisture (driver side front hard-line to hose connection). I re-cleaned that spot because i couldn't tell if it was some remaining fluid I didn't soak up or an actual leak. Master cylinder volume looked good.

Did a couple more laps w/o issue. No visible leaks/moisture from seeping brake fluid upon re-inspection. I stopped & had some dinner @ my local pub. Was driving over to my GF's house & when I slowed to turn onto her street the truck shuddered. That's definitely new. My mind immediately went to 'ABS' shudder as the default issue. I parked @ her house, grabbed a flashlight & inspected all line connections & bleeders. Everything was still dry/clean. The fluid is still full (same level).

I guess tomorrow @ lunch I'll pull the wheels off & check braking surfaces for moisture or fluid. No dash board ABS warning either for what that's worth.

Thoughts? Look-outs?