[Serusers] fifo weirdness - removing then adding same alias causes it to zombie

I've noticed that if you remove then add the same alias to the aliases table a couple of times in a row, it'll zombie on you. To be precise, if you do an "serctl alias rm ..." followed by "serctl alias add..." a few times in a row, the alias will vanish from the aliases table. This happens regardless of whether the db_mod from usrloc is "1" or "2" (in debug mode, you can see the vanished alias refered to in the log msg - "removing spare zombie (wt)", which seems to indicate that the contact record got flagged as zombie in the replication/deletion process.) To play safe, I wrote my own perl/fifo script to do this. Still the same error... (fifo files are - :ul_rm:aliases\nfoo@bar.com\n\n :ul_add:aliases\nfoo@bar.com\nsipbaz@veg.com\n0\n1.00\n0\n128\n\n Any idea? Is this expected behaviour? cheers