In the attachement you find a DWG to reproduce the faulty behaviour.
1. run the BATTMAN command
2. change the name of an attribute Tag (e.g. SPACENAME to SPACENAME2)
3. hit the button "Apply" to apply the changes to the Block Definition (applies the changes to the block definition e.g SPACEINFO)
4. hit the button "Sync" to propagate changes to existing block inserts and their attributes (applies the changes to all block instances in the drawing).
The existing values of this attribute (e.g. SPACENAME) in the existing blocks disappears instead of retaining the old value !
The correct behaviour of BATTMAN in AutoCAD is to retain the old attribute values of existing blocks inserts by changing the attribute definitions !
Am i missing something (...a variable) ?