Though it's a continuing puzzle to me why ESPs have worse ADCs than the rp2040, given their relative maturity. (Neither is particularly good, mind you, but I'm generally ok with the rp for my toy applications.)
Speaking of relative maturity, I just had a heap corruption debug for a few days. Imagine my surprise when fixing the issue involved switching from the default ESP32 BLE library to the NimBLE library...
I have been having an intermittent issue as well, but only when using BLE, so I was suspecting the Espressive drivers. I was wondering if it would be worth switching over to NimBLE, so thanks for that tip, I'll try it out and see if the problem goes away. Luckily, it's a very low priority.
If you read through errata and compare editions of the tech docs, it becomes apparent ESP32 has a history of silicon problems with its ADC's - through a few generations of their chips. In some models they removed huge swaths of related functionality from their documentation because it was bugged.
They're slowly getting better but analog is hard and I suspect they haven't prioritized it as much, historically.
