I’ll let @bigjosh follow up on the mismatch as I would like to recreate this.
A couple of notes that might be helpful
- setting the switch to unpowered is the way to go (it seems that the switch made its way out in powered and unpowered states, but it should only be in unpowered since the battery is providing the power)
- 3.4v on the battery is surprisingly high, I believe they start at 3.3v and spend most of their life between 3v and 2.7v on the low end. This could be an artifact of the powered programming.
- If you take out the battery and try programming with the programmer set to powered, does that work? This would point to a bad battery.
Looking forward to figuring this one out 