PvP achievements in Mercenary Mode

[Therougetitan]

Was trying for Out of the Fog and did not get the achievement after defending two bases.

Do all achievements not work mercenary mode or is it select ones?

[Alfakennyone]

I hear it's pretty glitchy in there, some people got achievements that they shouldn't have.

[Lord Pebbleton]

Don't rely on mercenary mode for achievement hunting.
To think, I once went into a RBG; it was Twin Peaks. We won 3-0, and I instantly got the achievement Double Jeopardy (win after being behind by a score of 0 to 2). I was dumbfounded, then I realized my team, albeit Alliance, was put on the horde side (against another alliance team of course). So the game counted US as our opponents, and registered our win not as 3-0, but as 2-3.
Sometimes it can be beneficial, but more often than not, it won't.