[locale.codecvt.virtuals] Possible grammar error

[cpplearner]

[locale.codecvt.virtuals]/3:

If returns noconv, internT and externT are the same type and the converted sequence is identical to the input sequence [from, from_next). to_next is set equal to to, the value of state is unchanged, and there are no changes to the values in [to, to_end).

I can't parse this sentence (these two sentences?). I think there's a grammar error in "If returns noconv".

For the reference, this part was added by LWG 19.