What is a good example(s) of such a form? I know that the general rule is to stick to the single-column pattern, but in my opinion, many of such "rules" come from people working on relatively simple websites. And too often, the reference is a registration/purchase form. I am thinking about business apps where users are using the form repeatedly.
I will insist on the good practice that you seem to already know which is to stick to a single column pattern. If there is a high volume of information that you need from your users in the context of a business app, then consider extending the form on multiple pages with a clear indication of completion progress.
The guideline for single-column forms is indeed being abused much too often. As you mention it relates primarily to single-use, data entry-only forms, like registration forms (although most consumer data collection use cases will also fit). They prioritize things like intuitiveness for the novice/occasional user and a clear path to completion with minimum friction. In the context of complex, productivity-oriented web apps, where forms are needed to display information more often than to update it, multi-column forms are not only acceptable, but are a much better solution vs a very long single-column form. The classic example are CRM and ERP applications, but pretty much any sufficiently complex web app will reach this point pretty soon.