OP confirmed that the server was initially serving only an index.html. In that configuration, the vulnerable code path is never reached — it requires a .php file.
OP added php-version.php roughly 18–19 hours into the experiment (I'm not sure of the exact timing), so that period should be subtracted from the publicly displayed challenge duration.I'm skeptical of the value of such setups, unless it's clear it's an out of the box setup, and we already know those are totally broken.
I don't understand who these people think they are really fooling. Is this some AI denial?
At first glance, this wouldn't affect demonstration of the vuln.