Before upgrading to GP Premium, there was no issue. but when I upgraded to GP Premium, 1776 URLs came in lcp issue for the mobile version.
My site is lyricsmusti.com
this issue is only for mobile
what is the LCP issue being reported ? I tested your home page and a couple of your posts and they were all below the recommended 2.5s ( ranging from 1.9s to 2.3s ).
The main LCP timing issue i see, is the Featured Image is being lazy loaded.
You should exclude the featured image from being lazy loaded to improve this.