I did not have this issue in 1.5 either but any vApp Template created/moved/copied in 5.1.0.810718 does. I'll file an SR today.
I've changed the query above for MSSQL to use variables in order to update the DB easier. Here's what I used to update our DB:
DECLARE @Catalog varchar(80)
DECLARE @vAppTemplate varchar(80)
SET @Catalog = 'catalogName'
SET @vAppTemplate = 'templateName' -- May need % at the end in case vApp Template was copied/moved. May get multiple returns though so be careful.
update network_interface set ip_addressing_mode = 1
where nic_id = (select nic.nic_id from network_interface as nic inner join vapp_vm as vm on nic.netvm_id = vm.nvm_id where svm_id=(select svm_id from vapp_vm where vapp_id=(select entity_id from catalog_item where name like @vAppTemplate and catalog_id=(select id from catalog where name = @Catalog))))
Eric