extended 2017 Form 5330 in error

Calendar year plan - we filed Form 5558 to extend the 5500 and the 5330 for a client.

Now we find that the late deferrals were not for 2017 but instead were for 2015 and 2016.

The client is asking to not file Form 5330 for 2017 because no late deposit of deferrals for that plan year.

Are there consequences for extending Form 5330 and then not filing one?

Thanks.

No