well it has been muted so it is sent at start of sequence and does not play (for want of a better term) that specific PC on that muted channel. Coz you know its muted.

least that is how it works for me. But I do not use track PCs as they act this way and is kinda a lazy PC control, meaning its very basic for basic use. It does not replace the usual use of PCs as it relies on start of looped sequence. Ok so its like a automatic gear in a way and does the shifting, or program changes, for you. So now its time to learn to drive a manual.
Its a mono synth right so that means you are sending those PCs to same channel but it has to hear them and can do both at same time. So one PC at a time right, There is a hundred ways to get around this and it depends on workflow. I for starters, would not use track PCs, make pads in a set with PCs on many different pads for quick voice changes in realtime as you play and can record this to. So that might be a bit advanced bit gives you an idea of what is possible. Program changes can be written into sequence. Plug in MIDI cable to you MPC MIDI in from mopho MIDI out to get PCs as you do them. Make sure Mopho is sending PCs first, then hit record and go for it. So this is a real easy way to put them in your MPC. Also do it by overdub + stop for precision placement of PCs anywhere you want this way. So of course you can just put them in sequence window as an event to. more complicated but good to learn. Every synth is different as well and can have PCs, bank select, MSB LSB ect. try above first.
OK so you have to figure out the way that suits you. I use PCs alot and can tell you its worth knowing how to program them. be it in realtime or programmed. or both.
Tip here. PCs can be silent or can glitch a synth as it plays note. try make PCs between notes. put one in every bar. problem solved. one in every bar on different tacks means when you unmute a track... yep you guessed it it sends a Program change and you get what you want