Tex. Prop. Code § 240.107
In the case of a disclaimer by an object or taker in default of an exercise of a power of appointment at any time after the power was created:
(2) if no fiduciary is then serving, the disclaimer must be filed:
Added by Acts 2015, 84th Leg., R.S., Ch. 562 (H.B. 2428), Sec. 15, eff. September 1, 2015.