I'm thinking The rest of the STOMP switches are non latching, so I'm with you there ..
But it might also work the other way round too, as in "hold the Tuner up" ? , who knows
It depends on the controller and the software side
As an example in PRESET mode the STOMP sends 1 program-change when depressing (release)
But in STOMP alternates 0 and 127 on every press
And then pressing and holding #4 send C41 127 (tempo, ready to learn tempo) then sends SysEx every 2 steps, probably the tempo value
I guess I'll find out when I plug something and see what is sending from ext1 & ext2