only 1 project showing interface is inactive !!! WEIRD

hi. (using a Mac)
I have 10.0 and 10.5 and was opening stuff between the two… thought maybe it was because of that. Maybe i did something to corrupt the file ?

I have Project A, which when i loaded it, shows no metering activity . and i hear no playback, and the various settings in STUDIO tabs show the UR12 as active and happy.
If i load an earlier version of Project A, the STUDIO setting show my interface is active and happy.
Any other project which i load , i can hear and the interface shows as active.

when something happens bizarre as this, i would think there was a corruption somewhere…
but isn’t it wild that my interface looks like its not being ‘interfaced’ correctly for this one particular project ?
Is it possible i disabled something somewhere in the interface configuration ?
to me, an interface either works, or doesn’t. If it works for a song, then all the drivers are up to date… etc…etc… etc…
it shouldn’t work for one song and not another.
(cue twilight zone music)