On a pattern I have a couple of P-locks on the FX track, to turn the delay feedback up then back to zero.
This works fine until I change pattern and the delay feedback reappears gradually. I have to manually put it to zero.
I am changing patterns well after the P-lock sets the delay feedback to zero and AFAIK there are no P-locks on the new pattern, yet the delay mysteriously reappears.
Thanks @Void - that might be part of the answer. The kit value for the delay feedback is higher than zero, but nowhere near enough for the delay to get as out of control and squealy as it does. The loud delay from the previous pattern has long since been silenced and its not residual sound from the previous pattern coming back through and bumping up the delay signal.
Maybe I need to double check the p-locks on the new pattern