That's great that it started working again. I'm sure we'll never know, but would be curious what exactly got broken in that problematic software update, and whether everyone tuning into Clear QAM was affected, or only those on specific cable systems.
Clear QAM is rare these days in the US, so there might not have been many complaints even if it was broken everywhere. Only small, independent cable operators still offer it. With the FCC no longer requiring this, major system operators like Comcast, Spectrum, and Cox now scramble everything, requiring a box on every television (so they can turn off cancelled & non-paying accounts without having to physically disconnect the drop), and some also implement Switched Digital Video as a bandwidth-saving strategy, where less popular channels are placed on a particular neighborhood's coax feed only when someone's actually watching them... or just sent as streaming video over the DOCSIS data carriers.
Does your Roku TV show correct program guide information for the direct-tuned cable channels? Lack of guide data is often a drawback with direct Clear QAM reception, since it's often sent to the cable boxes on a proprietary side channel that customer equipment can't understand, but I think Roku (like Tivo) gets its program guide over the Internet, so maybe it "just works" regardless?