When recording a pledge payment or a regular contribution, if the amount includes a comma (such as 2,500.00) then the amount recorded is just the number to the left of the comma
This can be reproduced in the public sandbox.
- Click "Create New... Contribution"
- In the total amount field, fill in 2,500
- Fill in other contribution details as desired
- Click Save
You will now see the amount stored as "2"