Entering a rate as 1000 causes the field to reset to 1

Hi all,
I’m having an extremely frustrating bug in my quotations docType at the moment.
If I try to set the rate field for an item to a value over 999.99 the field resets to 1,10,100 based on the magnitude of the value I enter:

Then after I click off of that field:

10,000 goes to 100 on click off


We don’t have any client/server scripts running at the moment, or any permission levels restricting edit access to this field.
It’s an extremely frustrating and crippling issue - please advise.

Thank you,