I found a very similiar leak on my 2014. Started as a static leak this summer. On a 200 km ride I might loose a tsp of coolant. I just tried sealing it with JB weld SteelStik and 500 km latter it is still fine. I know welding is the best option but the hole was smaller than a pin head and the pressure won't exceed 16 psi so I thought I'd give this a try.
The picture you show of the weld bead shows an addition bead at the end. The weld beads did not fuse properly. So you have a tight seam that the coolant is leaking through. The correct way to fix it is to TIG weld it with the coolant out of it. It is in a tight spot and a 2011. I'd try the epoxy first. Carry some extra coolant when you ride too. I have heard of other people having good success with epoxy, even from stud damage.
I had a leak on my 2011 gade but it was from towing a broke down Yamaha I slowed down the sled tunk the back of mine his bumper went below my bumper and broke the cooler in a bout the same place as yours I took it to a friend and he tig welded it up I did drain the coolent and removed the headlite pod seat and gas tank tail lite snowflap bumper and drain the oil out of tha motor so we could hang the sled upside downside so it was was easer to get at
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