Bead seal leak
 

Recently both rear wheels in the matter of a week apart have developed a inside edge bead leak, tire shop did a reseal but recommended refinishing the rims because they said it would likely return over time. Is this something that happened because the car was a FL car/ humidity related?

Is it corroded?

It's possible.

Are you using Nitorogen? It would be better because Nitrogen doesn't retain water. If the product is delivered from a clean source.

If using shop air, the compressors will retain water if not dried properly or drained etc. They will just pump that moist air into your tires. This will in turn be exacerbated by the humid Florida air.

Good shops will have dryers installed inline with their compressors. Saves power tools and prevents moisture ingress.