On the Rules page, if the "If amount" value is changed for an existing amount-based split rule, the split percentages get messy.

Instead of maintaining the percentage field of the splits, the amount field of the first split is kept, leading to a change in the percentage field.

If it's to be split in more than two parts (eg. split in three), the amount field of the first two splits will be maintained, and the amount of the last split will try to balance things out to reach the new amount in the "If amount" rule.

Changes to the split amounts or percentages don't save, so they cannot be corrected manually.

Example:

If original rule was for $100 and set to split in three ($70 = 70%, $20 = 20% and $10 = 10%), if the amount is then changed to $50, the three splits will be ($70 = 140%, $20 = 40%, and -$40 = -80%).