Reading the Physics.SE question What is the current physical theory of what causes the 'Morning Glory' roll cloud over Northern Australia? (pictured below):
Image source: NASA Astronomy picture of the day 24 August, 2009 of a Morning Glory roll-cloud over northern Australia. The origin and processes are quite well understood.
In the paper linked in the answer: Travelling Waves and Bores in the Lower Atmosphere: The 'Morning Glory' and Related Phenomena (Smith, 1988), the author expressed an uncertainty in his concluding remarks, which are the basis of this question:
The structure and origin of northeasterly morning glories is relatively well-understood, although questions remain about the precise mechanisms inhibiting the leakage of wave energy to the upper atmosphere, and the transformation of disturbances over the land during the day when the original wave-guide is destroyed by convective mixing.
The italicised portion suggests that some mechanism(s) prevents these effects from occurring, resulting in the roll-cloud persisting.
What meteorological factors maintain the Morning Glory roll-clouds?