Thanks Chris KB1ZNLW for this detailed explanation and workaround. I had a similar issue with my 80-20 unit, except that in my case the voltage off the divider was VCC rather than 0V, but lifting the lead of T401 indeed resulted in it going back to the expected 2.5V.
I used a 47pf capacitor, as a guess/what I had on hand, and that works well enough that I can receive lots of WSPRs using WSJT-X on both 40m and 20m (and maybe other bands as well, but with reduced sensitivity, of course). I'll be able to play with it while I wait for my DigiKey order. ;)
THANKS!
73 JRJ W9IYN
cube1us