Bet the boots that hold the carbs were leaking. ...between boot and metal intake....after pulling and pushing after new reed installed can make them leak..
A good mig guy could fix it in place...not the strongest fix...but lets talk about why it broke....
Is that bolt not the oem botl?....if it has slop in the hole in sure thats why it broke
Plug on right looks like it had more heat....if carbs are set the same ...do a quick leak down test. ..just to make sure that side doesn't have a leak.