Amazon Advertising ACOS skyrocketed 2 days...

In short my ACOS went from average 35% (consistently with the odd day getting up to 75% now and then over the past 9 months.

Now from 20 to 22 November it shot up to over 300% -

What is the reason? Possibly due to thanks giving... However I am thinking perhaps this indicates Amazon are using bots to click on adverts (my reason is over these 2 days I am still getting clicks but with an incredible drop of sales...) Obviously this is speculation but I would be interested in what other sellers are experiencing on these two days.