NTMB / Dual Volume Question

[NKT]

Greetings:

I saw quite a few NTMB posts, but nothing that seemed to address the issue I am having. I have an NTMB & NTMB3 with the 3 EQ pots that was wired just like the diagram on Bartolini's website. I replaced the Vol (25K) and the Blend (Dual 250k) with two Vol pots (250k Rev Log).

Everything seems to be working just fine EXCEPT when both Vol pots are turned all the way up. If the Neck Vol pot is turned up 100% and I bring the Bridge Vol pot up I get a distinct tone change as the Bridge Vol pot gets to 100%. As I rotate the pot between 90% and 100% I can hear a distinct tone change along with a little scratch. I am confident it is not the quality of the pot because 1) These are brand new mil spec pots and 2) if I switch the process where the Bridge is turned up 100% and I bring up the Neck Vol pot I get the exact same thing.

I could probably live with this but would really like to understand what is happening. Do I need to maintain a minimum level of resistance which I go below when both pots are at zero?

Any help is greatly appreciated. I am a new member but a long time lurker. Thanks!