You must be playing a different ptr than some of us if you think bb radius didn't change. I'm rocking a level 95 bb this season and been testing ptr bb, regardless of tooltip the radius nerf is quite noticeable....
not from my experience, literally dont effect monster beyond your character aura radius. unless they changed it some how before I stop playing ptr. the range of blood boil on ptr are hot garbage vs live, I one shot thing all the time with in 10-15 yard radius on live. it might have something to do with demon nerf who knows, but game play wise ptr definitely not as smooth as live. and definitely wouldn't top firelock in terms of clearing speed.
I tested it repeatedly and found the tooltip changed but the actual radius was completely unchanged
So unless they put some secret server-side only no-download patch for blood boil in the days after I tested it, there's no way it changed
I specifically tested for exactly that radius, doing a comparison of tile distance for blood boil on PTR, blood boil on bnet, and nova on bnet because we were also comparing nova/bb aoe (bb is about 1 tile larger radius because of how aoe collisions extend the 8 radius on nova vs ~10 on bb being center to center)
this is what it looked like;

testing vs spire since its nice and immobile and can be hit with sunder for nova anyway, trying to line up X axis and find furthest tile I can hit from
and I also confirmed that the patch had been applied to the version I was testing, because blood boil radius was listed as nerfed on the tooltip and demons were very plainly nerfed with lower hp / no conviction / couldn't bind super uniques and sigil lethargy does literally nothing