Sindragosa 25hc

heya,
I have a question for fellow raiders and raid leaders...
We are progressing in our guild (sometimes killing Sindragosa on 25hc, sometimes not, luck dependant), other bosses except LK are more or less on farm.
My question goes like this (talking specifically about Sindy25hc):
Does unchained sometimes run out a few seconds before blisterring happens in last phase aswell in your guilds? This basically results in a wipe since you simply dont have time to rocket boots to other side of her and die over there because you loose stacks almost directly under her, killing everyone in the process...?
DBM timer on blisterring is also off for whatever reason sometimes (I remember there used to be a bug with curse of tongues messing up the timer but it was since then fixed) is the bug back? or what am I missing?
It feels like avoiding exploding sometimes is pure luck since it depends if you get second unchained in last phase aswell or not? Keep in mind, our dps isnt amazing since we are progressing but its enough and should be doable...
What am I missing? Or how does your guild handle unchained in last phase?
Shouldnt the unchained reset at blisterring or just a short time after and not before?

The timers are sometimes off quite a lot yes, so they should be more of a general tip when to expect Blistering Cold.

I suggest, especially if people are not yet experienced in the fight, to just completely stop casting when they get Unchained Magic. That way, you can minimize explosions. Casters may use Wands to auto-cast, to do some damage, since that doesn't give UM stacks.

Try to coordinate raid cooldowns (Aura Mastery, Divine Sacrifice) when Blistering Cold happens, to minimize damage to the raid.
Regarding damage to the boss, it really depends on how you position Tombs in the last phase. To play it safe, I suggest putting the first and second Tomb into melee, so everyone resets their Mystic Buffet stacks (which will help with healing and survivability of the raid). Then just put other Tombs on the side and focus damaging the boss. You will definitely have enough time, since enrage timer on Sindragosa is quite long.

Other tips include everyone pre-potting for more damage and rotating cooldowns throughout the fight.