tabularray longtblr caption doesn't align left

Question

I created such config

\SetTblrTemplate{middlehead, lasthead, foot}{empty}
\SetTblrStyle{head, caption}{halign=l}
\newlength\lwidth
\setlength\lwidth{0.7pt}
\NewDocumentEnvironment{tabl}{m +b}{
    \begin{longtblr}[caption=#1]{hlines={\lwidth}, hline{2}={2\lwidth}, vlines={\lwidth}, columns={halign=c, valign=m, co=1}, width=\linewidth}
        #2
    \end{longtblr}
}{}

Usage:

        \begin{tabl}{caption}
            1 & 1 & 1 \\
            1 & 1 & 1 \\
            1 & 1 & 1 \\
            1 & 1 & 1 \\
            1 & 1 & 1 \\
            1 & 1 & 1 \\
            1 & 1 & 1 \\
            1 & 1 & 1 \\
            1 & 1 & 1 \\
        \end{tabl}

It should align caption left but setting \SetTblrStyle{head, caption}{halign=l}, but it doesn't do. I get:

I wonder if I understood something wrong, or is it a bug? I found that someone wrote his own config to do this here.