I don't know if moisture in the crawl space could cause it, but it seems odd that it is just in the corners.

Exterior water penetration is usually a bonus I have found.  

So, if you're planning on acquiring properties in affected areas, I would suggest you become an expert at moisture mitigation, mold removal, have the capital to weather another hurricane and the possible event of your insurance provider declaring bankruptcy and going belly up after such an occurrence.Consider this: https://www.theatlantic.com/technology/archive/2017/08/why-cities-flood/538251/*Houston, including its roads, parking lots, sidewalks, and other pavements, along with asphalt, concrete, brick, stone, was originally developed on land that, not for it's development, would have naturally absorbed water.

Make sure to have a cement board backer with an appropriate moisture barrier.  

Recommend installing to facilitateproper airflow and avoid possible moisture damages to attic space.

Outside items (like furniture) are subject to expanding and contracting as well as anything subject to moisture or mildew/mold. 

The problems came with these when they were insulated and skirted causing moisture to get inside the cavity and rot the wood and keep the insulation damp.

I just bought a bunch of this for a rental unit and it looked extremely durable (10 mm thick, resistant to moisture etc).

If the previous smoker was a heavy indoor smoker (probably the case in light of the lingering smell) then the odor can penetrate sheetrock more than most people realize. 

But at the same time scary here some of the issues:-Wiring/Electric issues: there were double taps and too small cables used-Standing water in half of the backyard (every time it rains harder according to the tenants)-One of the AC units is from 2003-AC air ducts are moldy-AC pipe in addict are crushed, insulation broken, taped with lots of air leaving-No drip pan and turn off switch for airhandler (2001) in one unit-Too little insulation-Moisture in the addict-Missing firewalls between the two units-One unit has copper pluming the other unit has recently received PEX, but where the wall was cut open to replace plumbing has not been closed and you can see lots of mold, mice droppings -One of the water heaters is sitting in water and mold on PVC and is rusting and leaking.