This is happening to a lot of websites, and Google is not interested in fixing this issue. Entire websites get deindexed over bogus DMCA. Why is it so easy to submit DMCA, while submitting counter DMCA takes forever. You have to enter one URL at a time for counter notice, while you can submit 1,000 URLs per text box and 10,000 URLs per notice when sending DMCA.
That's beyond terrible. That's a sure-fire way to kill a website. Sadly, there's no way for Google to determine, at first anyway, if those are legit or not.
I understand, the part that's insane is having to press a plus button and copy and paste each url into a text field. Also, the lack of notification of any sort