ETH Staking Rewards on CB

Has anyone noticed their rewards sometimes go down? Very slightly, but I've seen it happen a few times now and if anyone on here can explain it, I'd love to hear…..and BTW I'm not talking about the dollar value of the rewards…I'm talking about actual ETH2 earned. Overall I've earned a considerable amount…I've been staked for sometime now but every once in awhile I'll notice the number is slightly lower than 10-12 hours prior…yes lol I do check it twice a day approx.