There was a case and it may have been incorrectly decided and not appealed (though I personally think the person prosecuted in that case was acting like a jerk and someone "brandishing" to scare away a real threat would have got off).
The problem comes from the limited exception to PC 46.035, which says you must be justified in USING deadly force to violate PC 46.035.
Some prosecutors apparently don't think PC 9.04 over rules PC 46.035.
Sec. 46.035. UNLAWFUL CARRYING OF HANDGUN BY LICENSE HOLDER. (a) A license holder commits an offense if the license holder carries a handgun on or about the license holder's person under the authority of Subchapter H, Chapter 411, Government Code, and intentionally fails to conceal the handgun.
(h) It is a defense to prosecution under Subsection (a) that the actor, at the time of the commission of the offense, displayed the handgun under circumstances in which the actor would have been justified in the use of deadly force under Chapter 9.