But I'll take the bait: I have noticed no such trend.

People did that before pandemic, they do it now. Some of them are performatively demonstrating that they are important, and therefore busy, and therefore tired. Some of them appear to have medical issues. Some of them have a cold but find lying in bed boring. Some of them are indirect-bragging about their heroic alcohol intake.

Not feeling great today? Keep it to yourself or at most tell people who depend on you for something critical today. Avoid all work that isn't urgent and important. Communicate as necessary and expected.

Other person not feeling great today? Don't ask them to do anything that's not urgent and important. Feel free to ping them via message on random stuff, they're not doing work-work anyway.

Any of that feel like too much? Person fucked up, they should have taken sick leave instead.

Signaling you are sick and working via a status message just seems like an odd choice. The pessimist in me looks at this as signaling for sympathy.

Sometimes I work slow, sometimes I work fast but either way it isn't other people's business to know. I always hit my deadlines, and if I can't I meet a deadline I communicate it as early as possible.