Some groups are syncing between Domino and Exchange. This is noticed by the following entry in the log file:
" Excluded | Rule: proxyaddresses=NULL"
This is caused by having the following line in the exclude.txt for that Connector.
mail=null
If there is no Internet Address for the group in Domino, the Connector is set to exclude that entry.
RESOLUTION 1
Populate the Internet Address field for the Group in Domino.
RESOLUTION 2
Remove the mail=null entry from the Exclude.txt file .