Apologies in advance for the multiple posts over the past few days. I've made significant progress in optimizing my store though, and just need a bit of a nudge in the right direction for the mobile speed.
I've managed to get my GTMetrix score to an A Grade (97% Performance / 93% Structure) for desktop. My PageSpeed Insights score varies between 93-97 for desktop.
However, the mobile score can vary anywhere from 29 to a high of 69. The last score before this post is 52 for mobile. What is causing this fluctuation and how can I maintain a high rating consistently?