When you pull it back down, align up the valve with the left / right lines in the piston, my moneys on it matches up to the outter edges of the valve.
Countless guys were told the same thing back in the day when ZR 800-900s (500's as well) would without reason, one day just catch the exhaust port and smash a piston.
Yes, won't physically drop in the other way.
I just started a thread over on HCS about new info on power valves hitting the pistons on the 600 to 1000 lay down engine. Buddy had just rebuilt his, 100 miles later it had marks consistent with contact from both outter edges of the valves.