This is likely due it being the beginning of the new quarter. As I'm sure you are aware ad revenue fluctuates a lot. However, there are patterns that we're able to look out for, and the start of a new quarter is one of those.
As a new quarter begins, advertisers tend to crawl back on spending and re-evaluate their budgets for the new quarter. This means that the ad revenue index often sees drops around these times: https://adrevenueindex.ezoic.com/
Take a look at the end of quarter 2 start of quarter 3 for the last few years. You can see that there is a drop (July 2020 off the norm due to pandemic )
On 1st day of a new quarter, and for the first couple weeks, we would expect ad revenue to drop.
More noticeably because towards the end of a quarter, advertisers rush to spend their budgets, so revenue usually grows in the run up to the end of a quarter.
So, if you notice a drop in EPMV/revenue in your Ezoic Dashboard on or thereabouts at the start of each quarter - don't panic. This is totally normal, and you won't be the only publisher experiencing this.
A really insightful article that goes into more depth as to why ad rates drop around this time >>> https://www.ezoic.com/ad-rates-drop-july/