This is one of those cases where there are two hostas with the same name. One is registered and, therefore, the "official" version of H. 'Spring Fever' while the other is a non-registered plant and needs to be renamed to avoid further confusion.
 

A seedling of H. 'William Lachman', this cultivar was registered by John Van Ostrand of Illinois in 2005. It forms a medium size plant with medium gold foliage that starts the spring lighter and gets darker as the season progresses. The leaves have a piecrust shaped margin. Pale lavender flowers bloom in July.

MyHostas Database says that there is also a cultivar of this name which was originated by Stuart Asch of Michigan.