That's simply not possible - if you hear something in the clear, then it was transmitted in the clear. Some repeaters were programmed, and this applies to all comms systems really, to pass through analogue and digital during the crossover period. Two groups of users could just exist together although it was a mess (here in the UK with business comms) because digital radios ignore analogue and analogues look for the CTCSS - but it sort of worked. With digital, it's problematic to get continuous audio from digital systems when signals approach the boundary level - and the stream gets chopped resulting in that Dalek like speech that stutters and slows, then cuts. In the UK we have had encrypted emergency comms for quite a while now and it's reaching the end of it's life and soon to be replaced. It is not foolproof with dead spots and other issues, but pretty much it has worked and also for the first time allowed ALL emergency services to talk to each other if the need arises. It never replaces digital with analogue. It's completely different and there is NO analogue fallback in the system - at all. You don't have analogue facilities in the box whatsoever. If you listen on a scanner, then you will be hearing things the digital users cannot. It's unlikely, but possible that maybe their system is dual mode, and they still have a few analogue radios that still work, but that's probably accident. Maybe if they do have a dual mode system, they kept the analogues for emergency backup - but encryption costs nothing - it's a feature of digital systems that takes just a mouse click to activate. All the hams are using digital systems now. I can pick up a radio, select a channel and have a chat with someday in the US, from my office in the UK. Ham systems have endless grief entering the right data in boxes to set things up, but once it's done it works brilliantly - but if everyone in the entire world put a tick in the encrypt box, and secretly shared the many digit number, then it would be useless to anyone without the key.
If you can hear plain speech = it was analogue, not faulty digital. Faulty digital is the sound of silence, or that horrible buzz saw noise - nothing else.