Anthony, just some questions here,
Did you removed the front panel, removed all of the old silicon and before placing it back, did you placed silicone in between the edge of one panel and to face of the other panel?
or
Did you cut the old silicone in a 90 degree and left alone the existing (old) silicone that’s in between the panels and thus you place a bead of silicone on top of that “sandwiched” existing silicone?
I’ve worked, when I was a teenager, on a glass company, I actually just worked in residential installations, but there was a guy in manufacturing who have done some of that job, filling seems in glass displays for stores, doing custom tanks, and to my days, this is still applicable, filled seems in a tank, the way manufacturer does, is a must, and practically, holds and helps more bonding resistance than filling a tank with the outside corner bonded to the adjacent panel, just check in some glass tank manufacturers, Deep Blue, Innovated Marine, etc, just check how they have done it, in some of them you can even see that they only relay in the silicone that’s in between the panels, and remove or leave the least possible on the face of each panel, I hope it makes sense.
A while ago, I was reading some DIY projects on R2R on repairing tanks, many suggested remove, clean, apply a bead in between panels, seat the panels, clean then excess just for looks.