I had opcache.interned_strings_bufferalready set to ugly huge numbers like 272 - and the warning came back anyway after few days. Restarting PHP-FPM service “solves” this (warning disappears) for some time, just a workaround at best.
It really doesn’t matter what (huge value) is set, the root issue - and if it’s only NC misleadingly complaining about it - must be another thing.