Yep, this is what I'm thinking. I just bought this bike. PO said he flushed and filled the system. I believe he only idled it for a few minutes. As I rode it it warmed up enough to open the cap and push fluid to the tank. But since the tank is blocked it simply leaked out onto the ground. At this point the system was low on coolant which could make it run hot. I doubt he burped it properly so it probably also had air trapped. Does that sound logical?
Any way I'm replacing the tank because it's obviously bad.
Usually a good burp can be had warming the engine with radiator cap off. Fill as the level falls.
2018 F-150 XLT SuperCab 4x4 2.7L
2016 Beta 430 RS
2016 Subaru Outback
2013 Tesla Model S 85
2009 Husaberg FE450
1983 Porsche 928S