I'll just quote what shorena said on the other thread. It could be someone who's just being happy fusing up inputs and at the same time, wants to somehow troll other people. It could be any of the three, really, but reason #3 is the most plausible of them seeing that no one has posted about inputting a wrong fee yet.
#1 human error (unlikely)
#2 some script messed up
#3 just a miner having fun fusing inputs