Slayer Exciter Interfering With Voltage Measuremnet With Multimeter
Things did improve for you when you placed the DVM further away from the offending Slayer coil.This shows that this is a radiation problem .I have found that cheap DVMs can give bogus readings when working on Transmitters and large SMPS .Bypassing the red and black clip leads did little to improve this .If this was a conducted issue then filtering the leads would cure it .These observations occurred with a cheap Dick Smith Electronics DVM  .There are now many chinese copies that look new but have the same old PCB in the shops waiting for some mug to buy them.In my experience the FLUKE does not do this .