And the plot thickens.. After giving the board a once over and heating up a few connections that didn't look bad/cold, but, just were not as "clean" as I'd like them to be, I decided to take another look, as had been suggested, at the power issue. I didn't see anything on the board that would suggest this issue was a cold solder joint that was intermittent or in some way causing a problem. I'm pretty sure I had verified my adapter was supplying a steady solid 9 VDC, but, much to my surprise (among other reactions), I was seeing the output drifting from as low as 7.2 V up to about 8.8...never reaching 9, and definitely not the stability of a regulated power adapter. Those reading were just with my DVM monitoring, so who knows how much this thing could have been varying under any kind of load. And as erratic as it behaved, makes me wonder if it was fluctuating enough to cause the ESP32 to behave erratically. If this is the root cause, the question of why it only happened in sleep mode, I have no idea, but I'll trade not understanding what exactly triggered the issue for a stable clock. I dug up another 9VDC/500 ma supply from my drawer full of power supplies, its running on that one now, we'll see how it behaves over the next week or so.

Anbei meine Implementierung in einem Outdoorgehäuse mit 2 großen Displays und integrierter STromversorgung! Mal sehen wie sich das Gerät im Alltag bewährt!

Hallo, Rainer, please, can you tell me the missing values of the resistors on distribution board? Many thanks, Ivo.

Well, since Saturday, with the new ESP32 module installed, the clock was rock solid; the issue had not reoccured. This morning, I was in my office, and I have a flashing dispay...the problem is back. The fact it ran fine for days (at least 7 sleep/wake cycles after replacement) has me really scratching my head. Going to give the board a good once over and make sure I don't have a cold solder joint I'm not missing, to where the replacment of the ESP32 flexed the board enough to where it chased the issue away temporarily. A long shot, I know, but easy to eliminate. I can also run it off of my bench supply to eliminate it being a power supply issue. I still see that as unlikely, but its one more thing easily eliminated.  

I get this from :  pins: SDA SDL ; I guess they sent me a malfuntućtioning  OLED-display ??