Last tested: May 2021
No, they do not. They will go on forever.
The only known way to kill the LookML Validator or Content Validator process is to restart the instance.
How long does the content validator take?
This can vary wildly depending on the number of Looks and dashboards on the instance. On one instance with 50,000 Looks and 10,000 dashboards, it took about an hour for content validation to complete.
Takeaway: If the Content Validator seems slow, it is recommended to wait it out rather than initiate it again. Starting the Content Validator again while it’s already running (eg by opening a new tab) will cause 2 simultaneous processes to run, and will not speed up the 1st process.