There are a couple of reasons why it may not be recognized but one of them is that it’s almost unplayable anyway in a conventional arranger fashion, ie lh below the split point. I would always play this chord across both hands, so it’s like a Bb chord in the rh with a C bass in the left. So it also almost becomes a Bb/C - a naming confusion which might be the other reason it doesn’t get recognized. It’s not unusual that essentially the same group of notes can be named as two different chords, or that it would take more than 3 notes to identify them, so you cant expect the arranger to recognize them all. Panos is right in that the sound is more important than the name. You probably need to add harmony notes to your rh to get the sound.
This sus harmony ‘sound’ is common in popular music, where for example Gsus9 would resolve to C, so it’s important to figure out a way to get it, but I think of it as F/G.
Mike