Bitcoin ETF Volume and USD Flow

Taking a look today at the charts for the top Bitcoin ETF's left me asking one question:

Is all this volume actually investors taking profits?

Looking at the volume for Grayscale (GBTC) and Blackrock (IBIT), the two top performing ETF's recently, we can see that there is a discrepancy.

While the volume is in the billions, the flow of USD is been minimal, and even negative on Grayscales charts.

Am I misinterpreting this? Any clarity would be more than welcome.

Appreciate the excellent dashboard @ante.

https://queries.santiment.net/dashboard/etf-volumes-728