Sorry, I unfortunately can't step you through the process of building obs-studio/OBS-MP, and I haven't taken a look at what the situation is with original OBS game capture, but I assume it's something very similar.
Couldn't really tell you when it'll be fixed, since it's a rather isolated issue, but you could drop by the Community Chat (click the red button in the top right) and check if any devs are around to give an ETA.