This only applies if you intentionally set either your post-derail respite or your autoratchet to zero. Which would mean you presumably expected to be able to derail twice in a row so it was pretty buggy that we’d suppress the second charge!
Anyway, if that’s you you should be getting an email like this today:
Subject: beeminder closing the double derail loophole (YOUR_USERNAME)
Hi, this is just a one-time notice that we’re closing a loophole you may have taken advantage of – wittingly or not – with derailing two days in a row. Normally you get so-called post-derail respite aka extra safety buffer after derailing so you can’t derail twice in a row and we’ve had a longstanding failsafe to just suppress any charge that tries to happen too soon after a previous charge, on the presumption that there was some kind of bug or technicality involved.
But you, YOUR_USERNAME, according to our robotic apiarian minions, have intentionally, on at least one Beeminder goal, set your post-derail respite or your autoratchet (aka safety buffer cap) to zero which means explicitly opting in to the possibility of derailing two days in a row.
So, hooray, as of today (er, yesterday) we won’t drop those charges on the floor anymore. You get more of the taking-your-money service for your money.
If you never even knew about this loophole, phew, no moral/info-hazard in telling you ex post facto. But in case you’d come to expect or count on it, that party’s over!
Thoughts, complaints, counterarguments, or bug reports very much solicited. Just reply to this email and a real human will respond.
Bethany, Danny, et al
P.S. Because this is a one-time notice about a change to your account, there is no unsubscribe link down here. If you want to never receive this sort of email from us again, you probably want to delete your account. You can find out how to do that, and find other email-related settings at https://www.beeminder.com/settings/account#account-details
Sound good? Huge thanks to @shanaqui for instigating the 
on this 
.
It’s funny how accidentally dropping some money on the floor like this is, in the unique case of Beeminder, actively user-hostile instead of accidentally user-beneficial. We even know of one user who went out of their way to set up an automated script to charge themself the dropped charge whenever this happened so as not to ruin the incentives.
Thanks