POE2 - Wrong Spirit usage with Bind Spectre/Filthy First-Born

Hi guys,
I used "Bind Spectre" to get bind "Filthy First-Born".

My character got 314 Spirit. Summoning one "Filthy First-Born" cost 132 Spirit with my current build. I support this minion with "Infernal Legion III", "Minion Instability", "Minion Mastery" and "Deathmarch".

If I summon two of them (264 Spirit) my character still got 50 spirit, as shown in picture (). Thats correct (314-264=50)


But after fighting for a while it happens that they did not revive and my spirit value (182/314) is strange. In this picture (
) only one revive and it shows that I do not have enough spirit to summon the second one. From time to time the spirit value is lower and none of them revive.

Sonetime a situation occure, that I can set the amount to 4, that is a higher value than possible(). They are not summoned and my reserved spirit is correct, but it looks like the spirit calculation with this spectre is wrong.

Maybe the reason is, that after dying they got this "explosion" animation.