I have seen an old Compact SI transducer look that way. Was nothing wrong with it. I guess the environment it was used in was the cause, it was on a pontoon boat.
Yes they are solid after assembly.
Humminbird Helix 12 CHIRP SI, Helix 12 CHIRP MEGA SI+ GPS G3N, 1198c SI, 1198c SI, ONIX 10 SI NT, Helix 7 CHIRP SI GPS G2,
Helix 7 CHIRP MEGA SI GPS G3, Helix 10 MEGA DI+ GPS G3N, SOLIX 12 SI, 360, RC-1