In the tool panel we have three indicator buttons, which show the current type of fill/stroke for the selection — Fill, Gradient, None.
Illustrator switches it to None, when an object with a freeform gradient fill is selected.

I can understand why it probably happens. Since freeform gradients are not technically gradients, and using this mode converts an object into a dynamic container for generating a triangular mesh, it makes sense for Illustrator to not display the proper indicator here — the container has no fill... but it makes no sense for a user. It is you who decided it’s going to be a gradient, it is given to use as a button in the Gradient panel, it should display the proper button in the coloring controls then also. Please make this consistent and respect your own rules.