"You tossed your Dirty Matty Bobblehead into the rift and a moment of calm is followed by a flash of red lightning, before the rift shoots out Rift-Touched Bunny Plushie!"

As far as I thought, the Rift-Touched Bunny Plushie was one of the items that you only get if the item you're tossing in has 'bunny plushie' in its name, but the thing I tossed in doesn't have the keywords in it. Is this a glitch or did something change?

neither a glitch nor a change, seems to be perfectly normal.

From RE: The Rift!

With respect to items like Rift-Touched Bunny Plushie and others that have keywords.