Natives Classic Bass not staying on pitch

I play in a trio with a singer, a guitar/bass player and me on keyboard.

When the guitar bass/player plays his guitar I handle the bass.

I Use the Clasic Bass found under Band in the Factory Library in Kontakt.

During our latest practice we found that the bass didn’t stay in tune. Each note started ok, then the pitch got a little up, enough that it was noticable, and that the bass player asked me to find out why.

Is this some kind of known problem? I’m not a Kontakt interface expert, so I don’t know if this is something that could be fixed, or if that bass just isn’t good enough and I should start searching for another one.

Did you try with Kontakt Standalone?

No.

Do you mean that this is GP related?

No he did not mean that - if it was GP related, all Kontakt instruments would be failing. Have you tried other bass sounds?

No. I settled for this one months ago, and we just recently found out. Just expected the Factory Library ones not to have that kind of problems.

Have another week before the next gig, so maybe I’ll have to look around for another standard bass…