Strange issue with keymaps?

So I have two keymaps set up so that most several keypresses on my main get converted into pressing a single key on my slaves to spam a castsequence macro.

Works pretty good as long as I'm pressing the primary keys that I have mapped (most of 1 thru 0). But when I try to press LShift-1 thru LShift-6 (which are also part of the master's keymap), nothing is happening on the slaves. No attempt to press the macro button.

I am using White Lists for keys to pass, and all keys in the keymap on the master are part of the White List (and some additionals that are not on the keymaps).

Thoughts?

Shameless bump...

This is still causing me problems.