Custom 'integer' field displays value even if empty on event confirmation pages

OK, this is pretty obscure but still an issue.

When you have a 'Select' custom field followed by an 'Integer' custom field.
Add them to a profile, in that order.
Add the profile to an event with a confirmation page

Register for the event, selecting an option from the select custom field, leaving the integer blank
Notice on the confirmation screen that the 'Integer' displays the 'value' of the select field above it.
If you register, the integer 'value' isn't saved, it's still blank. It just displays incorrectly on the confirmation page.

Edit: The issue is slightly broader, and seems to be related to the 'integer' field type. If you put a 'number' field before an 'integer' field then the preceding number will appear on the confirmation page if the integer if left blank as well.

But all this only seems to happen on event confirmation pages - not contribution page confirmations.