I have to agree with tile and the OP. Even if you have a dedicated formal writer for writing formal documents like briefs or proposals, every engineer should be decent at writing. Especially now that more and more communication is asynchronous.
I've worked with many engineers who couldn't write, and it always came across in the aspects of the work mentioned in the thread — less ability to parse error messages, to describe things to others over email/Slack/comments, and most critically, to understand things that others wrote. Fundamentally, a huge amount of engineering is reading and writing. And I find those skills are very often linked.