Hey Zig Zag,
Do you have a MIDI cable going from SP-16 back into Squid? My first guess is that the SP-16 is sending MIDI data back into Squid when you hit the touchstrip. Unless there is a compelling reason to do so, you only need a single MIDI cable going from Squid to SP-16 in order to slave SP-16 to Squid's MIDI clock and start/stop controls.
Let's start there to find out what's going on. That sounds to me like quite an annoyance and musically unwanted!