I’m seeing similar messages in the logs recently, using the current version of WP-Optimize (3.2.14), without webp conversion enabled:
‘PHP message: PHP Warning: unlink(/home/redacted/htdocs/wp-content/uploads/wpo/images/wpo_logo_small.png.webp): No such file or directory in /home/redacted/htdocs/wp-content/plugins/wp-optimize/vendor/rosell-dk/webp-convert/src/Convert/Converters/BaseTraits/DestinationPreparationTrait.php on line 96;
I’ve just realised that this is a PHP 8 specific bug.
In PHP 7.4 and earlier 0 != ” is FALSE whereas this is TRUE in PHP 8
