I wonder if your meter doesn't have a fault and is leaking voltage out. Placing a voltage higher than the chip supply on a pin will cause some chips to latch-up.
If you have any small signal diodes to hand like 1N4148, temporarily solder one between pin 1 and 2 with the cathode at pin 1 and that will prevent pin2 getting a higher voltage - but I have wondered if feeding something into pin 2 via a series capacitor (as the one from the LFO does) cannot under some conditions "pump up" voltage on pin 2 and cause lockup.
