The electrician(s) came by and verified that they are seeing 8 volts unaccounted for.
The phrase "unaccounted for voltage" is not descriptive enough to be meaningful. for example, do you have 8 volts too much or 8 volts too little?
For troubleshooting, the proper voltage measurements to be made are (some places might have 2 hots, like at the service panel):
Power
Line/Hot to Neutral
Line/Hot to Ground
Neutral to Ground
Cable
Shield to Neutral
Shield to Ground
Center to Neutral
Center to Ground
Measurements need to be taken at the service entrance,at each receptacle feeding the equipment, and at the affected equipment. It would also be helpful to make these measurements both when the equipment is connected to the cable and when it is not.
