My understanding is that after a cvr/fdr (airplane "black box") is recovered from water/ocean it is stored in a container of water until it can be properly cleaned just before trying to recover the data. It is said to help prevent corrosion or other problems that might prevent data retrieval.
I wonder the condition of the phone when found on the boat (submurged in water, rain exposure only etc) and if any additional precaution to preserve the electronics were taken.