Grace day not applied with backdating

[Anna Goben]

While clarifying how grace days work, I discovered that grace days are not applied in the case that backdating is in place.

Example:
Item is due on Tuesday at a library that offers 1 day of grace. Item is retrieved from the overnight drop box on Thursday morning. Item is checked in with a backdate of Wednesday, which should have still been grace eligible, but instead the patron is fined for 1 day.

Since patrons are told that grace days are offered and have met the terms under which they should be eligible, the billing system should also void the grace day's fine if the backdate lands on the grace day.

Software version: Evergreen 3.1