When the Dauntless is chasing the Protostar in PRO: "Mindwalk", Tysess gives the order to merge the "warp bubbles" of both ships, the first time we hear the term being applied to a warp field.
When the Enterprise is unable to go to warp in SNW: "The Elysian Kingdom", Spock theorizes the nebula may be affecting the ship's ability to create a "static warp bubble", and from context he's talking about the warp field generated by the nacelles.
Prior to this, the terms "warp bubbles" and "warp fields" were not used interchangeably, the former being a “static warp bubble”, previously established as a toroidal, non-propulsive subspace field which once trapped Beverly Crusher in a pocket universe (TNG: “Remember Me”) rather than the field used to enable warp speed travel.