The issue is still persist in the latest update too (3.1.11). Because of this, the webpage is not rendered successfully. I also noticed that this issue only affected certain pages, not all of them. refer the warning message below.
Warning: strpos() expects parameter 1 to be string, array given in D:\InetPub\vhosts\xxx.com\wp.xxx.com\wp-content\plugins\wp-optimize\minify\class-wp-optimize-minify-fonts.php on line 203
My observation: there is something wrong with ‘ Converts google font api version 1 font specification into API V2’ function.
The 3.1.8 version does not have this problem.
Please check and rectify. thank you.