Could this be silicone failing

[ducati1212]

Have a RedSea Reefer 350 and just noticed some discoloration on the silicone. Could be odd lighting or just nothing or I guess failing silicone.

Any thoughts? The lower edge on under the sand you can see lighter and darker.

add one of the side.

 

[piranhaman00]

Check with flashlight with reef lights off hard to tell

 

[ducati1212]

Check with flashlight with reef lights off hard to tell

Looks jet black with lights off and a flashlight. Nothing odd. Im not 100% sure what I would see if it was failing