Drop in rankings! Caused by decrease in pages crawled per day.

Recently seen a large decrease in pages crawled per day. Also see a significantly high increase in time spent downloading page. See images below.

Does anyone know what would cause this? I've had a look around online and people are mainly suggesting its due to high page load speeds. But the site isnt noticebly slow on any tool.

This does kind of coincide with the yoast issue I wrote about a few weeks ago.

bump