Not a bug. An Estate that inherits Crossroads is still an Estate by name -- not a Crossroads. The card wording says you get actions "the first time you played a Crossroads this turn". For questions like this, a great place to go before filing bug reports is http://wiki.dominionstrategy.com/index.php/List_of_Cards_by_Qvist_Rankings
, where you can find links to the wiki pages for all cards, which will usually have answers for questions like yours. For example, from http://wiki.dominionstrategy.com/index.php/Inheritance
: "If Estate inherits Crossroads, then playing an Estate can't give you +3 Actions because it's not "the first time you played a Crossroads this turn". But if you play an Estate and then
a Crossroads, you do
get the +3 Actions from the Crossroads, since it is
the first time you've played a Crossroads."