I do not think those are good grounds for doubting my hypothesis. I agree that fee bids are not posted randomly, in fact I think the stats clearly show that such bids favor 1sat per byte and higher.

If your hypothesis is that this effect is due to removing a range of bids all at once, then I think it is non-explanatory: if the filters have no effect, then fee bids ought to show up with similar frequently in the nearest values on either side of 1 sat per byte, because the range removed by each block is just as likely to leave transactions unmined on one side of that value as on the other.

But in fact fee bids do *not* show up with similar frequency in the nearest values on either side of 1 sat per byte. They favor 1 sat and higher. A better explanation is that something makes it harder for users to *set* feerates lower than 1 sat per byte; and in fact, most wallets don't *let* you do that, because they were designed with the filters in mind.