I have two smart actions configured in my account/app.
These have been working for at least a year.
Both are smart switches (HS200) triggering smart plugs (HS110).
They stopped working recently. Don't know exactly when.
The switches and the plugs can be seperately controlled.
To experiment, I added a 3rd smart action with unrelated devices. No luck. Then deleted and re-created the existing smart actions. No luck.
Then I tried doing the same with IFTTT, but as it turns out, Kasa is not listed as a trigger service ("if" category), but only an action ("then this").
So basically, it's broken.