'tmsh config sys load' causes monitors (healthchecks) to fail

Thank you for the best practice information but that's not what the question was about. While it may not be recommended to directly edit the bigip.conf file, there is no other way in 11.4 to change the name of an object (pool, virtual server, etc). This was the reason we modified the file, based on the advice of F5.

Also, the verify command was run beforehand and it did not catch this use-case. We've brought this to F5's attention and it has been confirmed that this is a bug. When you delete the send string in an HTTP check the F5 config does not have an entry that simply says "", it just removes the line entirely. That's how the default "GET /" check gets loads on a tmsh load, as the F5 assumes that the check uses the send string of the parent profile (HTTP in this case) if none is specified.

Should we be using the HTTP check without a send string? Definitely not, it was done because the generic send string does not send HTTP version headers and that caused an issue with our Tomcat and Nodejs servers. We've since found a correct send string but the old ones had not been changed. However, at the end of the day F5 config allowed us to not specify a send string and it shouldn't have overwritten our empty string with the default on a tmsh load. We appreciate the best practice advice however the question was "Why would loading the config modify all of these health checks?" and it's a bit frustrating when we mostly just get best practice tips.