I remember reading about there being a bug on Xbox One that makes it impossible to get this achievement if you’ve already done all the challenges on Windows 8 or Windows phone.
Does anyone know if this is also the case on the 360 version so I don’t have to waste my time?
Also is there a fix coming for this?
I have a feeling this thread might be about Spartan Assault. You should try asking a moderator to move it to the appropriate section, you’ll have better luck getting an answer there, I think.