If it's the AVR don't get why it would be especially bad for one disc, but hard to notice on any others.
Rocket Man/Mammy Blues are two 1970s recordings, is the distortion there on *all* tracks on *both* albums? Or just that short moment on one track?
Here's the stereo version
https://www.youtube.com/watch?v=AX8EnTgtBZ8
The part you seem to be pinpointing is where the string section plays staccato in low and high registers, starting at 1:40. It's somewhat harsh on the recording itself, especially during the louder, higher half. You might be mistaking that recording quality for distortion in your AVR.
I played the Rocket man half again tonight and it sounded crystal clear, then i played the Mammy blue and for the most part it sounded great, but i did notice a very few times there might be just al little distortion mainly at the start of the next song. I also played the stereo layer and pretty sure it was slightly distorted coming just from the front speakers. Also got the DV Chet Atkins double yesterday, sounds great. Guess i'll just let it go for now and if it is my reciever, it will probably get worse and i should notice it more often. Thanks.