There have been a few bugs fixed since then which could plausibly cause memory writes to the wrong location (including to some random point in the map array, at some very low probability).
As the bad tiles are (almost) numerically sequential and the contents of the tiles makes no sense at all, this is my current hypothesis on the cause.
Yeah I'm thinking the same thing myself, I recall 0.22.2 was a tad glitchy, but I didn't think it was severe, mild at best, well now I question that.
Your savegame crashes on load, so the tile blanking would either need to happen moderately early on in the load code, or the crashes need to be mitigated enough that the game loads.
Either way you would need to make suitable edits to the code, compile, load, save, and then remove any temporary changes to the code.
In the case of this savegame, I added some checks to a few places in the viewport code so that I could look at/around the bad tiles, and then added the tile blanking to an unrelated action that was convenient to trigger manually.
Fascinating & very intriguing!
And much thanks for the fixing! I'll continue my work on it, and who knows, an MP server for the scenario is in the works (using your patchpack), so if y'all want to see the final version and found a company in it, just look for the "Kaylorne Island - Voxren Province" server in the future! This scenario is designed for MP usage, and as y'all can tell I made (in several cities) company lots vacant for MP usage, so when someone joins the server and wants to found a company, they have certain cities have allocated measures, but cities that I haven't even touched, I can't hog the whole map
Take care for now, and again thanks JGR for the fix! You're awesome (as is your patchpack - can't live without it (vanilla doesn't cut it for me any longer LOL!)) And now, back to work on the scenario..
P.S. The English/German hybrid "reason" or the scenario is a special topic for me; it's dedicated to my late friend who was born in Germany, who died 10 years ago (at age 19, shortly before his 20th...actually in about 50 hours it would've been his 30th birthday (July 19, 1988)), he taught me a lot about German (and European) culture, so having an English/German hybrid with a touch of French here and there (I am a French-Canadian after all!), is a fascinating tribute to him, and I knew he'd love it too, he was also a TT fan (we met in Grade 1 but we were friends right until the end).