All Notes Off errors

I’m getting odd results when receiving an ‘All Notes Off’ CC from multiple keyboards on different channels… (That’s 176+chan,123,0 if I remember correctly).

My All Notes Off commands are definitely set to the appropriate channel for each keyboard, however EVERY channel is responding, so if I take my hands off any one of them the others go silent as well.

I realise I can filter out ANO, but seems odd that this happens. Am I missing something else?