Places generally along the South Freeway (I-45), and south of the Ship Channel, including Clear Lake, Deer Park, Freindswood, the Hobby Area, League City, Pasadena, Santa Fe, South Houston, and Texas City.
Considering this was a major film that grossed nearly $50 million 1980 dollars (approx $165 million in 2021 dollars), a scene depicting southeast Texas with the San Gabriel Mountains visible in the background is a huge error that should have been corrected during post production.
I'll add to the closing line of my original message by stating: "Texans expect portrayal of scenes representing locations in Texas to be at least reasonably accurate."
That probably explains why the series "Ozark" is filmed in the Atlanta area, and not in the actual Lake of the Ozarks.
Sometimes this can come back to bite the filmmaker. I've heard that at the Houston premier of "Urban Cowboy" the audience burst into laughter, because when John Travolta stepped out of his trailer, the famous mountains of Pasadena TX could be seen in the distance.
The reason for filming scenes depicting Galveston TX in New Orleans LA is likely due to the better tax incentives the state of Louisiana offers compared to those the state of Texas offers. This is also the likely reason scenes depicting Galveston TX in the 2018 movie, GALVESTON, were filmed in Tybee Island GA. For accounting purposes, tax incentives are treated as income; the better the tax incentives, the higher the income. Cost of production in Galveston TX is probably comparable to cost of production in New Orleans LA or Tybee Island GA. In summary, when the costs of production are comparable, it makes good economic sense to chose filming locations in states offering the best tax incentives.
The downside of filming scenes depicting places in Texas in other states is the possibility that many Texans expect scenes depicting Texas to be filmed in Texas.