When driving the DB BR 425 on any route, when you switch SIFA to unisolated the yellow/black exclamation mark is not shown on the HUD. This means you either need to look at the dimly-lit dashboard in the train or wait for the alarm.
I believe this is still on the list of things to be fixed. It was last on the roadmap 26/1 but has since been removed (due to the roadmap V2 changes) [Improvement] Add Safety System Indicators to the HUD
