Source

beamer / base / beamerbaseframe.sty

Diff from to

base/beamerbaseframe.sty

       \beamer@initfirstlineunskip%
       \ifbeamer@plainframe\nointerlineskip\fi%
     \beamer@checkframetitle}%
-    {\end{beamer@framepauses}%
+    {\par
+    \end{beamer@framepauses}%
   \egroup%
   \ifx\beamer@frametitle\@empty%
     \setbox\beamer@frametitlebox=\box\voidb@x%