ISM audio and meta out-of-sync in decoder

Similarly to what was reported to MASA in #350 (closed), the same issue likely exists in the ISM decoder: the output audio is likely out-of-sync wrt. the metadata when the delay compensation is disabled.

I think that the problem is not so critical in ISM as it is in MASA because in ISM the metadata represents objects' positions and not spatial coding parameters but I think that any misalignment is not desirable.