Semrush shows huge drop in referring domains/backlinks

I noticed the other day that from February 2021 until now, Semrush says we had a massive drop in referring domains (from 10,000 to 6,900) and backlinks (16mil to 2mil) but I cannot figure out why. Any thoughts as to how I can investigate this? The referral domains looks to just be fluctuations on the graph but the backlinks issue is a huge crash on our all-time metrics.