Yeah, those readings made no sense to me, and when the AC was consistently between 2.2 and 2.3 times the DC, I figured something wasn't kosher.
I've got an old Radio Shack Micronta 22-291U, It says 20,000Ω/V DC and 10,000Ω/V AC. Not sure if that helps. I think it's at least 30 years old. Nothing in the manual about a blocking capacitor.
Open to suggestions for a better DMM. I'd like a good compromise between top-of-the-heap and price, but not leaning too heavily on price if the compromise is going to have me disappointed and needing yet a better one down the road. I get the impression that the Flukes tend to be more idiot proof, but there sure is a premium to be paid for that. I'd be open to a bench meter if that saved me some money, because I can do pretty well with what I've got when it comes to portability. You know, troubleshooting vehicle electrical problems and such.