[LyX/2.5.x] Fix closing of local CJK language with polyglossia (#13315)

[Juergen Spitzmueller]

commit 8406a6d48dab7448556743614cd988d5540d557f
Author: Juergen Spitzmueller <spitz at lyx.org>
Date:   Fri May 15 12:56:15 2026 +0200

    Fix closing of local CJK language with polyglossia (#13315)
    
    (cherry picked from commit 761599050378c1699ab89ce9f70e11059f0d4722)
---
 src/Font.cpp | 3 ++-
 status.25x   | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/Font.cpp b/src/Font.cpp
index f2af680d6f..5a949d454c 100644
--- a/src/Font.cpp
+++ b/src/Font.cpp
@@ -643,7 +643,8 @@ int Font::latexWriteEndChanges(otexstream & os, BufferParams const & bparams,
 
 	if (closeLanguage
 	    && language() != base.language() && language() != next.language()
-	    && (language()->encoding()->package() != Encoding::CJK)) {
+	    && (language()->encoding()->package() != Encoding::CJK
+		|| (runparams.use_polyglossia && !language()->polyglossia().empty()))) {
 		os << '}';
 		++count;
 		bool const using_begin_end =
diff --git a/status.25x b/status.25x
index a8152dd57e..708f54886a 100644
--- a/status.25x
+++ b/status.25x
@@ -55,6 +55,8 @@ What's new
 
 - Fix problem with nesting of languages.
 
+- Fix closing of local CJK language with polyglossia (bug 13315).
+
 - Prevent duplicate theorem definitions (bug 13302).
 
 - Fix case where the colortbl package has been loaded unnecessarily