This issue has been around since the APEX update on Stratis and Altis.

When the Game Master places a structure or wreck from Tanoa, non-apex owners are kicked a few moments after and non-apex owners who join mid-game are unable to join, as they are also kicked instantly for missing apex content. When a non-apex player is kicked, a system message appears describing they're missing apex content. This issue is consistent across all Official Zeus Servers. Placing down APEX vehicles and AI does not cause this issue.

I believe this is unfair for all players, regardless of whether they own apex.
It's unfair for the Game Master, as they are unaware that placing apex structures will kick players. It's also difficult for them to avoid placing apex structures, as you can't distinguish between vanilla and apex structures in the CREATE tab since they are mixed together. For example, under the Wrecks there are vanilla as well as apex wrecks and you can't tell the difference.
It's unfair for non-apex owners , as they joined a vanilla session in the first place. So they shouldn't be so severely punished with a kick.
It's also unfair for Apex owners. I own Apex. I hate it when our driver, or worse, our glorious leader gets kicked while we're doing an escape mission.

Game Masters on Official Servers have tried to avoid this by making players aware, but it still happens frequently.

It would be nice to have a system similar to virtual arsenal, where apex content indicated with a symbol.