Fatal error during optimization process when unexpected extension

[remyperona]

Describe the bug

PHP Fatal error: Uncaught TypeError: strtolower(): Argument #1 ($string) must be of type string, bool given in imagify/classes/Optimization/Process/AbstractProcess.php:595
Stack trace:
#0 imagify/classes/Optimization/Process/AbstractProcess.php(595): strtolower()
#1 imagify/classes/Job/MediaOptimization.php(181): Imagify\Optimization\Process\AbstractProcess->optimize_size()
#2 imagify/classes/Job/MediaOptimization.php(66): Imagify\Job\MediaOptimization->task_optimize()
#3 imagify/inc/classes/Dependencies/deliciousbrains/wp-background-processing/classes/wp-background-process.php(516): Imagify\Job\MediaOptimization->task()
#4 imagify/inc/classes/Dependencies/deliciousbrains/wp-background-processing/classes/wp-background-process.php(333): Imagify_WP_Background_Process->handle()
#5 /home/jpegr0/public_html/fta/wp-includes/class-wp-hook.php(324): Imagify_WP_Background_Process->maybe_handle()