TS-3329, we changed the ATS start up behavior to fail to start if any of the entries of ssl_multicert.config fails to load. This changes the functionality of ATS in from 5.2 to 5.3.
For many/most use cases, this is a desirable change. However, for some use cases, you want to serve and start up even if some of the entries fail to load.
We will add a records config entry proxy.config.ssl.server.multicert.exit_on_load_fail
It will default to 1 on 5.x. May want to change the default to 0 when we move to 6.0