Is that normal? If so, clown on and I'm a silly goofball. If not, is this common?
Is it "normal"? No. Is it a problem? No.
How long is that vertical "crack" you are worried about, 1 millimeter? Less than 2 mm? Would you even see it - the vertical "crack", not the horizontal seam - without extreme close-up photography or magnification? If you hadn't noticed the normal seam at that location and had your attention drawn to it, would you have even noticed that minuscule "crack"? I would consider to be more of a blemish or scratch than a crack. If you went over all of your guns with a fine-tooth comb like that who knows what you would find.
I took a quick look at my Model 60 last night when I saw your thread. There is an actual arched gap on mine. Your seam is tighter than mine at that point. I'm really not worried about it. As the threads I linked to showed, it is a common mistake for people to think the seam between the side plate and the frame is a crack. It isn't and it isn't something to worry about.
Now, if you want to worry about some real cracks, there have been reports of lightweight J-frames cracking under the point where the barrel screws in. That's where you should be keeping an eye on things.