RED RING in Chaos Trial is bugged/invisible. This was reported 8 months ago.

The red rings can be invisible if they originate offscreen / you approach them from afar just before they explode, or if you move up/down on the elevator pedestals.

This has been reported here since April or earlier - at least disable this modifier til patched. After seeing how long this bug's persisted I'm gonna quit this season and hope things improve.