Thanks for the responses Nick and Dave!
I looked at the Hilltopper schematic tonight, and code to see how the encoder pull up was handled since it didn't appear to have any.
The encoder I am using is a KY-040; inexpensive and has 3 pull ups built in. I removed them, and configured the code and hardware to approximate the Hilltopper encoder, but used 220ohm instead of 470ohm resistors in series due to junk box availability.
All in all, between the 100uh chokes on the LCD power, and the revised configuration of the CLK/DT/Button pull up/supression, I don't seem to be getting the popping, but the PLL still unlocks occasionally ... Which still sucks as it involves shutting the rig off/reset and looses my place ;)
Before I made these changes though, I did play with separating the dial and frequency updates, and minimizing the LCD display routine to one lcd.print line.
The problem actually got worse, and that may have to do with Dave's insight on update times.
I'll continue to play with it. If I can't ""fix it"", I may just blame the corona virus ;)
, Ron WB9YZU