Tank Breaking/Coming Apart?

I recently tore down my 55 gallon to move, but I was planning on storing it until I can use it again. However, I noticed one of the corners seems to be different than the others. The pictures will probably make it easier to see the issue than me trying to explain this. The crack has been there for over a year now with no apparent problems. However, I noticed the silicone seems to have bubbled up in places, and that's definitely a new development. Does this mean that seam is coming apart? I can't tell if this is something I should worry about or not. Figured asking experts is easier than finding 55 gallons on the floor later!

Yup! Just emptied it two days ago. I also realized the pictures are sideways; sorry!

As far as I can tell the bubbles happened after I emptied it, but for all I know it might have been there for awhile when the tank was full and I just never noticed. I had a feeling it was looking like a potential leak, so I'll probably just chuck it and buy a new one when I decide to set something up again. Thanks!

On a side note, this tank has been a brat! Haha I already had to replace the top once (broken center bar). Probably a good thing I noticed this!