After doing this mission on four characters I have come to the conclusion that skipping KotFE prevents HK-55 from becoming a companion at the end of the Arma Rasa alert. On two of my characters that I skipped to Ossus with, HK-55 remains unavailable as if he were still dead after the chapter "Taking Flight." The other two characters received him correctly after going through the first nine chapters. I believe this may be because the decisions that are made automatically for you when you skip KotFE are bugged in some way.
It is worth saying that I didn't have an issue like this with Z0-0M, she was recruited successfully on all four characters.
https://imgur.com/a/Tc4yom7
Picture of the bugged HK-55
