I think i found the cause.
On the redeploy i get 2 log statements like so
2008-01-24 10:46:52,602 DEBUG [org.jboss.cache.loader.JDBCCacheLoader] executing ddl: drop table jbosscache^M
2008-01-24 10:47:19,415 DEBUG [org.jboss.cache.loader.JDBCCacheLoader] executing ddl: create table jbosscache(fqn varchar(255) not null, node blob, parent varchar(255), constraint jbosscache_pk primary key (fqn))^
This smells like
cache.jdbc.table.drop=true
cache.jdbc.table.drop=false
cache.jdbc.table.drop=false