Create new post first shows charge of ~3 billion rcs, then suddenly account is charged ~28 billion more rcs? [UPDATED]

The account "@leatherdog-games" made the following post: https://steemd.com/playbypost/@leatherdog-games/chess-pupmisfit-vs-muksihs-round-12-blacks-move-game-5125783 

I was watching steemd to see how much the post would cost. The account had about 23 billion RCs available.

After the post the account showed about 20 billion RCs available.
I did another refresh and the account now shows a deficit of about -7.8 billion RCs. The total charge appears to be 10x the original charge. Is there a node not using the 10x latest patch that is injecting bad data into the network? (Is rc plugin is largely non-consensus?)

Is there something else going on?

If a node can "inject" higher RC costs at least part of the time that  general settings should not be causing, then this can easily be  exploited as a denial of service attack vector.

GITHUB ISSUE: https://github.com/steemit/steem/issues/3005

UPDATE

Ok, they closed the issue with:

Roughly 30 minutes ago, api.steemit.com full nodes relaunched with a reindexed 0.20.5. Steemd.com uses these nodes for querying RC data. The discrepancy you are describing is most likely the transient state correcting itself. Until all witness upgrade to 0.20.5, some transactions which don't meet RC requirements may make it into blocks -- which the other witnesses will see as driving RC negative.

So my questions are (and are added as comments to the closed ticket).

• So comment costs are now 10x the previous cost? We've rolled back to pre 20.4 costs? Or is steemd just showing an erroneous charge / balance remaining?
• Or is it the comment options set auto called by my client library? (if that is the case, isn't that how beneficiaries are set?)

If it is the 2nd option, then how much damage will this change cause to dApps such as @dtube?

Anyone have a clue as to what is going on here?