Update:
My ADC feature request on Espressif’s BBS has had 118 views. Unfortunately no word from the developers. This might mean I have to add an ADC chip to the design.
The problem:
I’ve been thinking about the level shifter and why it was causing my software to crash. 10M Ohm and 10pF capacitance are very small loads. The software crashing just because a scope probe is connecting is very bad.(stating the obvious)
The hypothesis:
Bidirectional level shifters are typically designed to react quickly to transitions and drive very weakly in the steady state. With the target pins unconnected the shifter is steady state and the scope probe might be enough to cause a problem.