Prius (2001-03) :: Gen 1 - Power Loss While Driving Down The Road / No Motor Output

This just recently started happening just shy of 200k miles, 14 years. While driving down the road, suddenly notice a power loss or no power, i.e., no motor output. Sometimes the just the ICE won't accelerate, sometimes it's both ICE and Electric motive force. When this occurs, the Brake and ABS check lights turn on. After a few seconds, to 10's of seconds, then the motive power reenables and the Brake/ABS lights go out. Often the cars continues on with no repeat. Testing over a few drives, it seemed to only do it during the warmup cycle when coolant was near 160-170.

However on a drive in the afternoon after it occurred in the morning; with ambient around 30 degrees, windows cracked, interior heat off, it didn't occur on the 15 minute drive, mostly freeway speed, even after about 10 minutes and cranking interior heat on. No codes are registered when this happens. I used Torque Pro and monitored things like throttle position and such, and things there seemed normal. Eng rpm dropped under 1000rpm and wasn't steady. Watching the MFG the power flows responded to the throttle (pushed/released) as if the engine was still doing what was asked (go figure, the display shows what is commanded, not what is occurring?).