TM1 has supported MDX for a long time, but TM1’s own “dialect” of MDX can be a little quirky. Compared to standard MDX TM1 can be very concise, but it is also ambiguous which can be a problem as using TM1's "shorthand MDX notation" it is only possible to tell by context whether a member, a member property, or a subset is being referred to.
Of course, TM1 doesn’t just speak its own dialect of MDX, it also understands standard MDX and using standard MDX solves solves the problem of ambiguity. However, there is still a potential for typing and name conflicts between TM1 attributes and built-in intrinsic MDX member properties. This article makes Planning Analytics developers aware of these conflicts and how to deal with them.