Grafana "failed to cast query to string"error log (k8s env)

Hi, I’m having “failed to cast query to string” error logs from the grafana pod.
I think each log count is the same with the number of rules i have(3 and its evaluated every minute), it seems like there is no problem in rule evaluation… but im not sure why i have this log in the grafana pod log…

my queries look like this:
labels.serverGroup:hi AND