It doesn’t make sense to repeat everything I mention on my own website and on the US Wizard forums, but I’ve basically discovered a bug with the Firebirds’s Finery set, where not all Unique and Super Unique monsters (Gold/Purple Elites) are subjected to the full 20-stacks ignited bonus.
Read what I posted on the US Wizard Forums : Firebird’s Finery Bug
I you also enjoy playing the Wizard, I ask that you please play Firebird’s Finery and try to verify this bug for yourself, and post your replies on the US Wizard Forums.
Prometheus Diablo Portal - Firebird’s Finery Bug
https://diablo.dzomlija.com/firebird.htm