In ARMA, voice and chat are tied in direct chat channel. I feel quite lucky for sorting out my problem, since no error messages has helped me.
I hope that help you. In case it does, please update the ticket setting "Reproducibility" from "unable to reproduce" to "Reproducible" or so, and the description/title accordingly. That should help the developers.
BIS should really investigate this issue, as Realtek Audio driver are quite popular and many people are subject to this bug (*1). Maybe not a BIS fault, though.
(*1)