Can my mortgage rate hold expire if a gap closing drags on longer than expected in Ontario?

Yes. A mortgage rate hold is tied to a specific expiry date set by your lender when the commitment was issued, and it does not automatically extend just because your closing is proceeding through a gap or escrow arrangement rather than in one step. If the gap runs longer than expected and pushes past that expiry, your lender may require the rate to be reset to whatever their current rate is at that later point, rather than honouring the original hold.

Because a gap closing is meant to be a short bridge rather than an open-ended delay, this risk grows the longer the gap actually lasts, which is one more reason lawyers try to keep these arrangements as brief as realistically possible. If you know or suspect your closing may involve a longer gap, raise this with your mortgage broker or lender as early as possible so they can tell you whether an extension of the rate hold is available and what that would involve, rather than discovering the expiry has already passed once registration finally happens.