Header affix script doesn't work if there's any module on left column

We're using custom JS code in script.js file to trigger the affix for header part. One part of the code is to subtract the left column with header column but if there's any module on left column, the script fail to execute. More detail can be found here https://www.joomlart.com/forums/topic/strange-behaviour-in-header-class-in-landing-page-load/