Being a former journeyman plumber, I noticed multiple issues in this crawlspace I inspected.
1. The copper flex line (top arrow) is not the proper way to connect to PEX piping (Could lead to future leaks and indicates that it wasn't installed by a licensed plumber).
2. The open red PEX pipe (right arrow) is the TPR (Temperature/pressure relief valve) from the water heater (The TPR valve allows excess pressure/heat to escape the water heater tank. This will lead to added moisture to the crawl space. Also it's not in view to monitor.).
3. The metal band iron strapping(bottom arrow)is in contact with the copper waterline (These two dissimilar metals touching will cause galvanic corrosion and lead to increased deterioration.).
Keeping you educated!