Bug in XPath 2.0 spec?

I think there might be a bug in the XPath 2.0 spec. I was trying to implement it in Java (using Sablecc). I get a shift/reduce error on a Multiplicative expression (when it is a treat expression followed by a +). This can conflict with the possibility of an occurence indicator (just a + sign). I fixed a few other similar errors and found I just had to be more precise in my grammar file. But this seems to be an honest ambiguity in language itself.

Is this a conflict in the spec? I've attached my error log and grammar file.

Tim