LaTeX subfloats:子標题標簽中的額外不需要的間隙

我試圖將两个圖像放在另一个旁邊，然後我註意到括號內的子標题之間有一个很大的間隙（？）！

知道如何避免這種情况吗？

\documentclass {article}
\usepackage {mwe}
\usepackage{xltxtra}
\usepackage{xunicode}
\usepackage{xgreek}
\usepackage[LGRx,T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[english,greek]{babel}
\usepackage{alphabeta}
\usepackage{subcaption}
\usepackage{kerkis} % Fonts
\XeTeXlinebreaklocale "el"
\setmainfont[
    UprightFont = Kerkis,
    ItalicFont  = KerkisItalics,
    SlantedFont = KerkisItalics,
    BoldFont    = Kerkisb,
    BoldItalicFont  = Kerkisbi,
    BoldSlantedFont = Kerkisbi,
    SmallCapsFont    = KerkisSmallCaps]
    {Kerkis}
\newfontface\bfsc{KerkisSmallCaps-Bold}

\begin {document}
\blindtext
\begin {figure}
 \begin{subfigure}[b]{0.48\linewidth}
\includegraphics [width =\linewidth] {example-image-a}
\subcaption{Κάτι στα ελληνικά}
\label{Figure:FIG_A}
\end{subfigure}
\hfill
\begin{subfigure}[b]{0.48\linewidth}
\includegraphics [width =\linewidth] {example-image-b}
\subcaption{Something in English}
\label{Figure:FIG_B}
\end{subfigure}
\caption{Εικόνα Α (Αριστερά) και Εικόνα Β (Δεξιά)}
\label{Figure:FIG_A_B[![enter image description here][1]][1]}
\end{figure}
\end{document}