Each T1 key contact system is a SPDT switch. That means that the entire CV resistor chain is in series with all the NC contacts. If any NC contact is dirty, then every key above that contact will not trigger.
The key contacts are the achilles heel of the T1. I finally got tired of dealing with dirty contacts and replaced them with the new contact assembly that synthfool.com sells, zero problem since.
As for multiple pedals playing the same note, sounds like a blown CMOS somewhere.