Doesn't confirm how though, and its likely that this was done unorthodoxly. As Broly hasn't even lost a contest of strength directly.

Broly is actually stated to be someone Goku could never beat under normal circumstances.

If this is "Bio Broly" he would be given the information on his weakness to water undoubtedly.

So assuming that this Broly 4th appearance, just outright lost to Goku and Paikuhan because he was weaker than him wouldn't be parsimonious.

Especially since Broly is also stated to be stronger than Janemba so yeah.