By far one of the most Frequently Asked Questions on the inkscape-user mailing list and the inkscape irc (#inkscape @ is about gradients.

They typically come in the following forms:
“Why are my Gradients are not moving when i move an object / shape?”
“Why is my gradients disappearing when i move an object / shape? “

This behaviour is not a bug, there is a feature in inkscape(which you can toggle on or off) that tells the gradients to move or be scaled when you scale the object that they are used in.

To toggle this behaviour on and off there is a little button in the tools control bar (for the selection tool.) It is circled in the screenshot below. If it is pressed down, your gradients will move when you move the object, if it is not, the gradients will stay put.