Is this Dynamic Texture being used as the base texture for a Sprite Game Object?
This is enabled by default, as we expect that will be the core use for Dynamic Textures.
However, to disable it, call RenderTexture.setIsSpriteTexture(false).
You should do this before drawing to this texture, so that it correctly inverses the frames for WebGL rendering. Not doing so will result in vertically flipped frames.
This property is used in the endDraw method.