Director trademarks not displayed

I noticed on a film's trivia page that this item was in the update form but not displayed on the trivia page:

DIRTRADE([link=nm0000005]): Theatre companies.

At first I edited it as follows, which didn't seem to help:

DIRTRADE([link=nm0000005]): [Theatre companies]

Then I added an explanation, and now the item is displayed:

DIRTRADE([link=nm0000005]): [theatre companies] Theatre and its staff featured.

I found the same item in the update form for this title, where it is still not displayed and I haven't added the explanation:

DIRTRADE([link=nm0000005]): [theatre companies]

The trivia guidelines say the explanation is optional:

DIRTRADE([link=nm######]): [trademark keyword]: optional explanation

DIRTRADE([link=nm######]): [flying]: the last scene of the film takes place on a hot air balloon

DIRTRADE([link=nm######]): [shooting on film, not digital]

I wonder if there are many other items that are not displayed.