If a numerical comparison: greater than or less than - is used in the automation, the automation stops if the sensor has the status "Unknown" for any reason:

"Unknown" status

if/condition/3/entity_id/0
Executed: May 4, 2023 at 7:20:27 AM
Result:
result: false
message: value 'unknown' is non-numeric and treated as False

Solution: Value Template

This can be remedied by using a "value template" in the automation: 

{{states('sensor.rain_zamg_12') | default(0)}}