Problem when calling controller method

Ok, just throwing things out there that I would have come across in personal experience and would check.

Sometimes database queries get cached on DB side, it takes long time to load original request, but any future requests for same query come up super quick.

Like you say, it does not make much sense that changing method name alone makes difference.

Maybe check if you have any queries running on DB, pretty sure I had similar case only recently where first DB query would not fail straight out, but just case 500 error, and refresh on same page loaded everything. It was SQL related issue in the end.

I really don't think this can be a DB related issue. Chrome says it can't find the CodeIgniter controller method I'm calliing, so it doesn't even reach the API call that makes the DB query part. Firefox had the same issue.

Usually to fix this I write a new name that has nothing to do with the original. In order to still keep some relevance, I translate the method name to portguese (my native language), so I can still know what the function does without having to look at its code. Its the only way to make it work. Its like CI couldn't find the route to the function, but I use the default routing mechanism (http://server/controller/method).