OK - Problem over. Just me being a dummy and panicking. I simply hadn't filtered out "registration changes" on the Midi Channels Received Page again since upgrading so when I sent a voice change on channel 16 (the default) to another module (JV1080) the XD9 picked this up and changed to the block registration of that number even though the registration function (light) had not been selected.

This wasn't apparant at first as there is no change until the pattern measure or selected introduction has completed and I change voices whilst waiting for an introduction to complete.

Sorry If I alarmed anyone - It really was worth upgrading to version 2.0A

Regards - Keith