I've had the same issue just reveal itself on my Helix Floor, which is out of warranty. The LED rings on the top and bottom bank closest to the expression pedal have both started acting up, and it's 99% the solder connection, as gentle pressure changes the behaviour of the LEDs when tested.
I'm getting some pretty steep prices for a replacement board, be interested if any UK-based owners have had a repair done to reflow or replace the LEDs, rather than the board. Hundreds of pounds to deal with a pennies-cost failure is hard to swallow.
