Although it seems surprising to those of us who are concerned about privacy and Wasabi's plan to use blockchain analysis to blacklist UTXOs, it's not surprising to see large transactions going through Wasabi's coinjoin coordinator.  The Wasabi team made it clear when they made their announcement last year that the primary reason for the decision was to attract institutional investment houses to use their coinjoin.

The large transactions make it more likely that it is institutional investors using Wasabi, and that could easily account for the larger coinjoin pools.