PHP warning in error.log

Hi,

I’m getting lots of php warnings related to jsmin.cls.php in my server’s error log:

2024-01-10 18:06:44.338212 [NOTICE] [872] [172.71.182.186:11372:HTTP2-1#www.xxx.xx] [STDERR] PHP Warning: Undefined array key “‘1′” in /usr/local/lsws/html/wp-content/plugins/litespeed-cache/lib/jsmin.cls.php on line 475
2024-01-10 18:06:44.338242 [NOTICE] [872] [172.71.182.186:11372:HTTP2-1#www.xxx.xx] [STDERR] PHP Warning: Undefined array key “‘5′” in /usr/local/lsws/html/wp-content/plugins/litespeed-cache/lib/jsmin.cls.php on line 475
2024-01-10 18:06:44.338249 [NOTICE] [872] [172.71.182.186:11372:HTTP2-1#www.xxx.xx] [STDERR] PHP Warning: Undefined array key “’10′” in /usr/local/lsws/html/wp-content/plugins/litespeed-cache/lib/jsmin.cls.php on line 475
2024-01-10 18:06:44.338256 [NOTICE] [872] [172.71.182.186:11372:HTTP2-1#www.xxx.xx] [STDERR] PHP Warning: Undefined array key “’15′” in /usr/local/lsws/html/wp-content/plugins/litespeed-cache/lib/jsmin.cls.php on line 475
2024-01-10 18:06:44.338262 [NOTICE] [872] [172.71.182.186:11372:HTTP2-1#www.xxx.xx] [STDERR] PHP Warning: Undefined array key “‘1′” in /usr/local/lsws/html/wp-content/plugins/litespeed-cache/lib/jsmin.cls.php on line 475
2024-01-10 18:06:44.338268 [NOTICE] [872] [172.71.182.186:11372:HTTP2-1#www.xxx.xx] [STDERR] PHP Warning: Undefined array key “‘5′” in /usr/local/lsws/html/wp-content/plugins/litespeed-cache/lib/jsmin.cls.php on line 475
2024-01-10 18:06:44.338275 [NOTICE] [872] [172.71.182.186:11372:HTTP2-1#www.xxx.xx] [STDERR] PHP Warning: Undefined array key “’10′” in /usr/local/lsws/html/wp-content/plugins/litespeed-cache/lib/jsmin.cls.php on line 475
2024-01-10 18:06:44.338280 [NOTICE] [872] [172.71.182.186:11372:HTTP2-1#www.xxx.xx] [STDERR] PHP Warning: Undefined array key “’15′” in /usr/local/lsws/html/wp-content/plugins/litespeed-cache/lib/jsmin.cls.php on line 475
2024-01-10 18:06:44.338287 [NOTICE] [872] [172.71.182.186:11372:HTTP2-1#www.xxx.xx] [STDERR] PHP Warning: Undefined array key “’25′” in /usr/local/lsws/html/wp-content/plugins/litespeed-cache/lib/jsmin.cls.php on line 475
2024-01-10 18:06:44.338293 [NOTICE] [872] [172.71.182.186:11372:HTTP2-1#www.xxx.xx] [STDERR] PHP Warning: Undefined array key “’50′” in /usr/local/lsws/html/wp-content/plugins/litespeed-cache/lib/jsmin.cls.php on line 475
2024-01-10 18:06:44.338299 [NOTICE] [872] [172.71.182.186:11372:HTTP2-1#www.xxx.xx] [STDERR] PHP Warning: Undefined array key “‘100′” in /usr/local/lsws/html/wp-content/plugins/litespeed-cache/lib/jsmin.cls.php on line 475

What could be causing these?