1. Go to https://en.wikipedia.org/wiki/Comparison_of_disk_encryption_software?debug=1#Operating_systems
2. Click twice on the "Android" column
3. Click once in the "Linux" column

Expected behavior
The table would be sorted by that column

Actual result

{
	"errorMessage": "TypeError: parsers[j] is undefined",
	"url": "https://en.wikipedia.org/static/1.26wmf13/resources/src/jquery/jquery.tablesorter.js",
	"lineNumber": 210,
	"columnNumber": 4,
	"errorObject": {}
}

from the line

cols.push( parsers[j].format( getElementSortKey( $row[0].cells[j] ), table, $row[0].cells[j] ) );

of
https://github.com/wikimedia/mediawiki/blob/1f54fccca868fa4862df95245957f3028c67336e/resources/src/jquery/jquery.tablesorter.js#L210

By the time the error happens, i===0, j===10 and parsers.length===10 (so there is only parsers[0] to parsers[9], and parsers[j] is undefined).