I wasn’t responding specifically to your query. This topic was crated by @DuffDan, and they said it could be a server issue. That part was not specifically meant for you.
There are more exotic situations where this might happen which I didn’t cover in the article. In part because I don’t know for sure if it’s actually the cause, and because there isn’t really a way to fix it.
It’s rare, but possible, to hit the EP limit without any PHP code. The EP limit is tied to concurrent requests. So it’s a combination of the number of requests per second and the duration of the requests. HTML and other static requests are very fast, whereas PHP requests are usually a lot slower due to all the code having to be executed, so high EP usage is generally is caused by PHP.
If it’s just a traffic spike with a high number of requests, then there isn’t a lot anyone can do about that.