Chronomancer Time Freeze with bosses phases

During the boss fight if you cast time freeze right before the next stage\animation boss could become invulnerable and even untargetable.

Happened with the "black crow" (untargetable) during mapping. I timestopped him right after first stage.
And with one with lasers from "duo of bloodlickers" from interlude (last pair of bosses). Second one should be dead from the Essence drain but was alive and targetable with no visible hp. I timestopped him durting the wall blood sacriface animation.
relogin does not help, only die and try again.

The part II.
Same boss "black crow" became untargetable after time freeze. Casted it almost instantly and dealt 30-40% dmg. Worst part is that it left untragetable even after respawn! started the map with 2 respawns coz it is black crow and it were not enough. Boss on blooming field is just not for chronomancer.