Why was the FDR of flight ET409 extracted from ocean transported dry instead of in water?
As posted on Avherald, Lebanon's CAA released the final report in January 2012, detailing the investigation and its findings. The link on Avherald is broken, the current site for the CAA can be found here. The front page still links to a page on the report, where it can be downloaded.

Section 1.11 describes the recovery and contents of the flight recorders, and describes both recorders as being "immediately packed in water.".

See this fragment:


  The DFDR was recovered from the Mediterranean Sea by the Lebanese Navy divers and turned over to the IIC in presence of members from the IC on 7 February, 2010. The DFDR was immediately packed in water to prevent/delay the onset of corrosion and transported to the BEA laboratory in Paris France under the custody of the IIC accompanied by a Lebanese and an Ethiopian IC members.


And this one:


  A thorough hand search of the sea bed was then carried out the Lebanese Navy divers who finally succeeded in retrieving the CSMU and handing it over to the D/ICC in the presence of members from the IC on 16 February. The CSMU was immediately packed in water to prevent/delay the onset of corrosion and transported under the custody of the D/IIC and an Ethiopian member of the IC to the BEA laboratory in Paris France, for readout on 16 February, 2010.


While this could be inaccurate, it's much more likely that the reconstruction missed this point.