I think it's been long enough since the announcement was posted to consider this a bug.
The latest anti-day-trading measures were implemented May 15th, but there's nothing in the rules about them. This is the full extent of information:
We are implementing an addendum to the sales tax that is based solely on the number of trades a team has made in the past 14 weeks. If you have only made a couple of trades, you will be charged the normal sales tax; if you have traded a lot recently, you should expect taxes that may be several times as high as the regular sales tax.
I think it's safe to say that that's insufficient. This needs to be integrated into the rules and there need to be some tables or formulas to illustrate the tax levels.