Zend certified PHP/Magento developer

no classes are being updated to body tag on page load in magento 2.3

every thing was working fine and suddenly the alignment of whole page changed on inspecting i found that the classes are not being updated in body tag in UAT on home page the body tag is

<body data-container="body" id="html-body" class="cms-home cms-page-2 cms-index-index page-layout-1column" aria-busy="false">

but in current env its showing like
<body> only