From pictures of DFDRs I find it remarkable that the pinger's (ULB) attachment to the memory unit (CSMU) in the Honeywell SSDFDR seems to be a rather lightweight affair. (The ULB is the smaller "can" affixed to the end of the memory unit.)
FAA regulations prescribe that the ULB shall be "securely attached" to the memory module, which is quite logical.
Each recorder container must:
(1) Be either bright orange or bright yellow;
(2) Have reflective tape affixed to its external surface to facilitate its location under water; and
(3) Have an underwater locating device, when required by the operating rules of this chapter, on or
adjacent to the container, which is secured in such a manner, that they are not likely to be
separated during crash impact.
Looking at the debris in this case I would not be surprised if the ULB has separated from the memory unit. That will probably not affect the chances of finding the memory unit now, but it may have contributed to the failure of the initial search operations.