Plot with Through[{f,g}[x]]… A bug or a misuse of Through[]?

I was expecting

Plot[{Sin[x], Cos[x]}, {x, -1, 1}, PlotLabels -> Automatic] 

and

Plot[Through[{Sin, Cos}[x]], {x, -1, 1}, PlotLabels -> Automatic] 

to give the same result, as

Through[{Sin, Cos}[x]] 

gives

{Sin[x], Cos[x]}

However I get this two different plots:

plot 1 plot 2

Is it a bug or do I misunderstand something? (maybe HoldAll Plot[] attribute does not mix well with Through[])

(I am running under Linux with MMA version 11.2.0 for Linux x86 (64-bit) (September 11, 2017))