No, but I have had turn on "thumps" when turning on the JC2/JC1 if I power it up cold from the AC plug. That is even if the JC2 runs its delay mute, I find that the mute time is not long enough to prevent these thumps through the JC1s.
When I measured the output of the JC2 to see the source, I found the DC levels were not quite zero (25 mV DC was enough to hear through the power amps). They did go down to 0.01 mV after a few more seconds, however. It appears that the DC servo control opamps in the JC2 take a bit of time to zero out after a cold power up, and need ten or twenty more seconds than Parasound programmed in to the mute delay.
So now I apply AC power to the JC2 and wait 30 or 40 seconds before I power the JC1/JC2 combo up and no thumps.
Most folks don't realize this, but the JC1 actually has three consecutive turn on delays. The first one is adjustable with the pot on the rear panel. The second one connects the main power to charge the large PS caps, and the third one unmutes the output connections to the speakers. In older JC1s, the delay times on the second and third delays can be shortened considerably due to bad electrolytic caps and poor zener diode voltages. So when you turn on a JC1, you should hear one click after the main delay, then a second one about 5-10 sec later, then a third one (and music) after another 5-10 sec.
I ended up re-building my timing boards to restore these delays. Each are important as they allow circuit stabilization to occur over the proper time period.