Unable to update Zapcat triggers in latest pre-1.8.3

I noticed when trying to update certain triggers I get an error message:

• Host key does not exist.Check expression part starting from ':jmx[java.lang:type=MemoryPool,name=CMS Old Gen][Usage.committed].last(0)}= {Template_Java:jmx[java.lang:type=MemoryPool,name=CMS Old Gen][Usage.max].last(0)}

  '

• Host key does not exist.Check expression part starting from ':jmx[java.lang:type=MemoryPool,name=CMS Old Gen][Usage.max].last(0)}'

However, the template exists and is assigned (and collecting data from the host). Also, this trigger is currently showing problem state so I know the trigger itself is working. I just can't modify it (at the template or host level).

I can modify other triggers just fine. I suspect it has to do with the format of the trigger. (FYI, this is a Zapcat template).