Managers not attending matches enjoy quick auto sub. Managers attending matches receive bonus procession but this is not important. They can get benefits for proper responses to live events and made sound in match changes.
Top of league table is not an explanation.
I use win bonus but I don't agree that it is important.
If opposite team had excellent pre-match preparation, they may still deserve to win without attending.
More matches are needed to prove if those not attending live match usually win. Probably your match result is one off.
Losses can also be explained by bad luck, poor team form starts, bad counter formation, inconsistent team performance, etc. These are some reasons I can guess.