Cloud Scheduler triggering Cloud Function via internal url - URL_UNREACHABLE-UNREACHABLE_5xx error

[rtb]

I've been running two cloud functions that are triggered by cloud scheduler cron jobs. They've been working fine for months until yesterday. Here is the log:

{"@type":"type.googleapis.com/google.cloud.scheduler.logging.AttemptFinished", 
"debugInfo":"URL_UNREACHABLE-UNREACHABLE_5xx", 
"jobName":"gcp_project", 
"status":"INTERNAL", 
"targetType":"HTTP", 
"url":"function_url"}

Nothing about the job has changed. Did Google update something or does anyone know how to troubleshoot? I've verified the url to the function is the same - again, was working fine for months.

Tried disabling and re-enabling the cloud scheduler api and created a new cloud scheduler job but did not work.