Certified GKH Gardening Expert
This usually happens with a lack of light or if the roots run out of space. Stretching will be a maple's response. Try increasing light or putting it into a bigger container, if that is where it is, with fresh soil and compost.
This article will help you with the care of maples: https://www.gardeningknowhow.com/ornamental/trees/maple/growing-maple-trees.htm