I've been using the Difference Tool in TunerProRT to compare bins, and notice a fair number of entries marked "Item Not Defined." For example, when I compare $0D bins BJFC and BDXK I get "Item Not Defined at address 4E31. I assume that something is going on at this address, as both of the bins have active values listed (40 and 28, respectively).

Can someone explain what's these entries are?