\begin{figure*}[htbp] \centering \captions...

figure* 是双栏通栏浮动体，标准 LaTeX 不会让正文环绕它；而且 [htbp] 中的 h 对 figure* 通常不起作用。原图高度较大，所以 LaTeX 容易将其放到单独的浮动页。

建议改成五张图等大的 3+2 网格，既更像论文中的标准消融/定性比较图，也能显著降低总高度：

latex
\begin{figure*}[!t]
    \centering
    \captionsetup[subfigure]{
        font=footnotesize,
        labelfont=bf,
        justification=centering,
        skip=2pt
    }

    % ---------------- Row 1 ----------------
    \begin{subfigure}[t]{0.315\textwidth}
        \centering
        \includegraphics[width=\linewidth]{
        AnonymousSubmission/LaTeX/iAdapter_pred_curves_SocialGood_h48_s2023_iAdapter.pdf}
        \caption{iAdapter}
        \label{subfig:social-iadapter}
    \end{subfigure}
    \hfill
    \begin{subfigure}[t]{0.315\textwidth}
        \centering
        \includegraphics[width=\linewidth]{
        AnonymousSubmission/LaTeX/iAdapter_pred_curves_SocialGood_h48_s2023_VoT_z_pos_pre_gpt2.pdf}
        \caption{Pre-GPT}
        \label{subfig:social-pre}
    \end{subfigure}
    \hfill
    \begin{subfigure}[t]{0.315\textwidth}
        \centering
        \includegraphics[width=\linewidth]{
        AnonymousSubmission/LaTeX/iAdapter_pred_curves_SocialGood_h48_s2023_VoT_z_pos_post_gpt2.pdf}
        \caption{Post-GPT}
        \label{subfig:social-post}
    \end{subfigure}

    \vspace{0.35em}

    % ---------------- Row 2 ----------------
    \makebox[\textwidth][c]{%
        \begin{subfigure}[t]{0.315\textwidth}
            \centering
            \includegraphics[width=\linewidth]{
            AnonymousSubmission/LaTeX/iAdapter_pred_curves_SocialGood_h48_s2023_VoT_z_pos_seasonal.pdf}
            \caption{Seasonal}
            \label{subfig:social-seasonal}
        \end{subfigure}
        \hspace{0.03\textwidth}
        \begin{subfigure}[t]{0.315\textwidth}
            \centering
            \includegraphics[width=\linewidth]{
            AnonymousSubmission/LaTeX/iAdapter_pred_curves_SocialGood_h48_s2023_VoT_z_pos_trend.pdf}
            \caption{Trend}
            \label{subfig:social-trend}
        \end{subfigure}
    }

    \caption{
        Qualitative comparison of one-step-ahead online predictions on
        a representative Social Good sequence over steps 0--168.
        Black and colored curves denote the ground truth and predictions,
        respectively. The methods exhibit different responses to the
        abrupt regime change near step 123 and the subsequent recovery.
    }
    \label{fig:social-prediction-comparison}
\end{figure*}

防止整图单独占一页

可以在导言区适当放宽双栏浮动体的排版限制：

latex
\setcounter{dbltopnumber}{2}
\renewcommand{\dbltopfraction}{0.95}
\renewcommand{\textfraction}{0.05}
\renewcommand{\dblfloatpagefraction}{0.85}

这里最关键的是：

latex
\begin{figure*}[!t]

而不是：

latex
\begin{figure*}[htbp]

figure* 最稳定的位置是双栏页面顶部。还应把这段图代码放在期望出现位置的前几十行，甚至提前放到前一段，因为双栏浮动体通常不能立即出现在源码所在位置。

如果三列后图中文字略小，可将宽度改为 0.32\textwidth；若仍然单独占页，则优先缩短主 caption 或裁掉每个 PDF 自带的白边：

latex
\includegraphics[
    width=\linewidth,
    trim=5mm 2mm 5mm 2mm,
    clip
]{...}

正文真正环绕图片只能用 wrapfigure，但它更适合单栏的小图，不适合这种五子图的论文级比较图。