Recruit the Vaal - Explore the Cuachic Vault boss bug

I started fighting the bosses Zelina and Zolin at the end of the Cuachic Vault. They killed me and when I resurrected at the checkpoint it won’t let me trigger the boss fight when I approach them. I restarted the game/ console several times and it still won’t trigger the fight..they just up on the platform extracting the blood from a victim. Please let me know how this can be fixed! Thank you very much!