Not sure if this is a bug but often when harvesting clay the clay chunk will drop under the coral and become impossible to retrieve.
-Have you tried reloading your save, game or console? No
-Have you tried clearing the cache of the console by shutting down for 2 mins before rebooting? No
-Is there anything else you tried to alleviate the issue? Please let us know whether it was successful or not. No
-Please feel free to provide any other information you feel may be relevant to this issue. NA
-Images / Links - If you have any images or clips of the issue happening, please include them.