TJ, Jonathan, Dave:
On the machine ext-alert (note dash, not underscore) we were running the legacy ext_alert processes alongside the new lv_alert. The legacy code was competing with the new causing GraceDB query errors.
I deleted the two services:
leaving just the lv_alert.service running. The deletion process I used is:
These services were subsequently restarted by puppet. Jonathan made the necessary manifest changes and these superfluous services are once again gone, this time hopefully for ever.