alt Hacker NewsKia just did this with their EV9 update - it broke CarPlay with a blank screen a few minutes into driving, which then reverted itself a minute later. Another OTA mostly resolved it. Neither of these updates explained what happened or what the fix was.
Let me be a devil's advocate here: you have essentially two options.
1. You write release notes thet contain technical details. Less than 1% of your customers understand them. More than 90% probably won't even care, let alone understand the document. And then there are the folks who get confused or scared and reach out to customer support with weird questions. This generates extra workload.
2. You explain nothing. The release simply is. The technically minded people are mildly annoyed. A few customers affected by open issues wonder if it's fixed now. The rest of them doesn't even care that there is an uodate and carries on with their lives. Customer service continues to complain about the usual bunch of random and weird customer issues.
It's quite natural to start doing (2) in a consumer facing business, isn't it?