My BX, received at the dealer in May had the zirk on the peddal but the tank still leaked. I think they are replacing tanks as needed but I do not think they have done a redesign. Note I am speaking of the main (black) tank, not the little (white one?) from way back, which I think was involved in a fix.
The BX is VERY capable for most homeowner / small farm owners. I love mine. It's not perfect. Seems they have their share of problems (small ones, not engine rebuilds etc). I bet all tractors are the same in that they probably all have small problems like that.
Rogue