I ran into something today that I've never seen: a way to convince MLS to accept an unbalanced donation.
I entered a contribution towards an AMFA account, but realized before I closed the batch that I'd entered the wrong AMFA account. Essentially, in the middle of the batch, I ran an income and expense report for the affected AMFA accounts, and noticed the discrepancy. So I edited the donation to reflect the correct account, and saved it. I then re-ran the income and expense report, but the discrepancy was still there. I went back into the donation, made sure everything was correct, saved it, but the I&E report wouldn't update to reflect the change. I went back into the donation, deleted the AMFA portion of the donation, closed the AMFA window, and then re-entered it.
Somehow in the middle of all this, the AMFA contribution doubled itself. That is, an identical amount was entered in identical categories. I don't know if I did that, or MLS did, but I didn't catch it. Not only did MLS not catch the fact that identical AMFA categories were used (something that usually sparks an error message), but MLS didn't catch the fact that the donation amounts did not equal the checks/cash for the donation. MLS allowed me to close the batch. The bank deposit was spot on, because the amount of checks and cash exactly equaled what was entered, but the total MLS batch did not equal the total of the bank deposit. And since the batch was closed, I couldn't change the amount of the donation when I noticed the error.
As I said, I'm not entirely certain how it happened. It's the first time I've ever seen MLS not catch a balancing error.