I have found multiple companies using the same job description in their job ads. Presumably, they are using a template rather than writing it themselves. I have also discovered unlikely phrases duplicated in multiple job descriptions. I suspect that these are a composite of multiple templates.

Have you observed this practice before?

I have observed and investigated the issue, and it is madding. When an HR department or hiring manager puts out a request for qualified candidates, the agencies scrape the text and put out the adds. They may use different titles, but basically the same description. Some modify the description formatting, but what you end up seeing is a dozen or more openings to apply for that are, in truth, all the same opening. If you apply for more than one of them, you are really applying to the same opening via different agents and are automatically disqualified.

This was a minor problem and caused rare problems 20 years ago, now it makes job seeking insane. Personal networking was always the best thing to leverage, but now it is critical as the technical job market is virtually unusable unless you get very lucky.