Thanks for the clarification, it makes sense., i.e. the detection is not "shaky" it's impossible to do!
I should have a coffee and study the source code for how that detection is done when signals are emitted across threads.
Coffee sounds nice, I'm now envious ... ;)
You can look here about the second part:
And, this "problem" with connecting to lambdas across threads should be documented better I think.
Perhaps you're right, but I'm too lazy to check what it really says in the docs ... :p
However I think it's documented, probably more emphasis can be put though.