It is not recommended to use more than one RadFormDecorator controls on a single page. However, if you want to this despite we do not recommend it, it is necessary to set DecorationZoneIDs and to ensure that each separate decorator decorates a separate zone. This being said, I suggest to wrap the desired areas which contain the buttons in a DIV and set this as a decoration zone for the first decorator and do the same for the textboxes and the second decorator and test again. If this is not possible for your layout, you should remove one of the decorators and use only a single one as the control itself is designed to work.
the Telerik team