Regardless of the language being used, I've found the discussion on naming conventions useful to explain something. M4 and V4 are both DAZ products, and are named to fit within the coded naming conventions of their software (aparently using paretheses...I don't use DS). Poser seems to be using a stricter convention with a definite distinction between text and numeric.

I just renamed Michael 4 as Michael X (left the space in) and subsequent copies came in as Michael X 1, X 2 etc. X is not a number.

I renamed him again to remove the space, and got Michael4 1, as with V4.

Why the space? Who knows. I think Michael is the only DAZ character name that ends with a letter that has an ascender, so maybe it was to make it easier to read. In any case, the naming convention suits DAZ's coding, and as it's their product, that's fine. Poser is also using a well known coding convention that distinguishes between text and numeric entries. It is NOT a bug. Also fine.

If it bothers you, fix it, it's easy to do. Doesn't bother me, this was just a curiousity.