It seems that if you set the value of a bonus to 0 in the original map (so not as a overridden bonus), the bonus link won't show once you start playing.
Is this correct, or am I doing something wrong?

If so, does anyone know a way to prevent this? I wanted a few bonuses that could be used to clarify groups (click on the bonus and see, for example, "all walls" or "all farms"), but didn't have any value.

Thanks in advance!

Bonuses that have a value of 0, won't show up during the actual game.

Right. Well, if there's nothing to be done about it, that's that. Too bad, but eh.

Thanks anyway!

Bonuses worth 0 aren't meant to show during the game. They never have.

Most map makers just set them to 1, as it's a very small amount that's not worth fighting over, and it can help the scenario creators immensely (Say they want to set "all walls" to stacks of 100 neutrals" :)

The bonuses can then also be overridden to 0 if the template creator wishes them to be :)

Also, Bonuses that are 0 cannot have a surveillance card played on them.

See 1v1 ladder map:

https://www.warlight.net/MultiPlayer?GameID=10422440

4 bonuses of 0, but do not show in games. Why would you want it cluttered with zero bonuses shown?