Here's a workaround for your popping problem: Signal the amplifier(s) off of the multi-zone DC trigger output on the 950 instead of the main one.

The proper way to start up or shut down ANY decent audio system is to turn on sources and preamp first and power up the amp(s) last. When you shut a system down the amp(s) should be powered off first, then the preamp, and then any remaining sources. By doing this you are virtually guaranteed to not get pops or other speaker damaging noise. Once you switch the trigger connection all you have to do to control the amp(s) is to turn on or off the multi-zone feature in the 950’s menu. I would also recommend engaging the multi-zone "MUTE" feature so that the amp(s) receives no input in this mode. You can still control the whole system from your recliner but it takes two or three extra keystrokes and those can be programmed into startup/shutdown macros if you like. I’m using three Aragon 8008ST amps with Klipsch Cornwall mains/surrounds and they will pop fairly loud unless sequential switching is utilized. By moving the trigger cable and programming the extra keystrokes into a macro on the remote you get the same ease of use without spending money. Obviously this won’t work for those who use the multi-zone feature for its intended purpose but I would be willing to guess that most people won’t use the second zone anyway. OR, you can buy a sequenced surge protector (Niles, Monster, etc.) that will do this automatically but prepare to give up $200.00 and up (mostly up) to get sequential switching.

As to whether a pop is "normal" or not, "normal" doesn't mean it won't eventually kill your speaker's drivers. Take the grilles off your speakers and watch the woofer cones when any "pop" occurs. If the cone is barely moving it probably won't damage your speakers but if the cones move very far (more than about 1/32") you're taking chances on your driver's longevity.