Suppose I talked to a coach about his team's performance. Suppose losing has never made him happy: (Ignoring singular/plural issues..)
"He has never been happy when the team lose."
"He has never been happy when the team lost."
Should it be "lose" or "lost"?
'Lose' or 'has lost' are both natural.
In that case:
"He has never been happy when the team lose."
"He has never been happy when the team lost."
"He has never been happy when the team has lost."![]()
I would not say that 'lost' is wrong. I think that the other two are more likely.