I wonder if it's the perfect storm of a couple of things:
•Plastic Nut - although the 650 has that too
•Newer Strings - in your clip the 650 sounded like the strings were much older than the EHB's
•Meatier Bridge - I've never seen an EHP up close, so I have no idea about how solidly the strings are held
***Fretboard Material*** - roasted maple is known for being on the "brittle" side. I own an SR1000 and the fretboard reminds me of an fretless I had with a CA (Super) glue coating. Snappy.
Individually I don't think any of these things would be that big of a deal, but in concert... maybe a lot of overtones… I think the story would be different if you are using a pair of DR's with the K3 coating, tape wounds, or maybe even flat wounds.
Thanks for posting the clips, it's always fun to find out that other people really analyze the same kind of things that I do