Intervals are showing odd numbers

One of my cards have a present interval of 14 days, ease 250% and interval modifier is 0.9
So the next interval should be 14 * 2.5 * 0.9=31.5 days
But the good option shows that the next interval is 2 month!
How to fix this issue?

It’s overdue. Due times after a break - Frequently Asked Questions