When a function returns a variable (or a pointer to one) that is statically located, one must keep in mind that it will be possible to overwrite its content each time a function that uses it is called. If you want to save the return value of this function, you should manually save it elsewhere. Most such static returns use global variables.
Of course, when you save it elsewhere, you should make sure to actually copy the value(s) of this variable to another location. If the return value is a struct, you should make a new struct, then copy over the members of the struct.