dark wizard my summons keep disappearing

[Fystikis]

hello i never played on interlude before so not sure if i do something wrong or its a bug when i summon my servitors they disappear after a while and the cooldown to resummon them takes a lot it happens both to silhouette and shadow im i doing something wrong or its a bug?

 

[Fystikis]

i noticed theres a green bar below servitors hp mp window and when that finishes they go away