Does the issue occur in the editor or during gameplay?
During gameplay
If it's a gameplay issue, please specify which movement system and camera type you're using (free movement vs. grid movement, third-person vs. first-person) or N/A if not applicable:
Grid movement with first-person view and real-time combat
Briefly describe the issue you're experiencing:
If a status effect with duration 0 (remains until it is removed again) is applied, this status effect does not appear in player.statuses.
 
Are there any errors in the in-game debug console or external console window?
no
Provide the steps necessary to reproduce the issue:
Apply status effect with duration 0 in console and print(player.statuses) to show codex.

Provide a download link to the bare bones project (if applicable):