I've just got an A7721 Bluetooth Keyboard and am having mixed results with keyboard shortcuts.
It's a bit hit and miss whether key combinations work.
In the Notes app from the Notes list on the left, Note List Search (Command + Option + F) doesn't work if you use the left Command+Option keys as part of the combination. Right Command+Left Option, Right Command+Right Option and Left Command+Right Option all work fine, but the logical choice does not work at all. It seems pressing Left-Command and Left-Option only sees the Command button being pressed down.
No combinations involving using the Command+Shift key work at all in any variation.
No combinations involving using the Option+Shift key work at all in any variation.
Command + any alphabet letter or square bracket works, but Command+ . or , do not.
The latter three issues I found were occurring using Slack (chat client).
The keyboard was set to iOS (Fn+A).
My guess is that perhaps Apple's first party keyboard has some magic to determine context and allow certain combinations through but I can't be sure.
I'm really unhappy though as this makes the keyboard somewhat useless to me, as I really wanted to use it for chatting in Slack.
I'm happy to provide more testing if required (even a Skype video call if you want to do some diagnostics) - physically the keyboard is excellent. I really hope you can get a fix for this.