diff --git a/src/pcre2_study.c b/src/pcre2_study.c
index 02d1c08..fc29969 100644
--- a/src/pcre2_study.c
+++ b/src/pcre2_study.c
@@ -824,7 +824,7 @@ if (caseless)
       (void)PRIV(ord2utf)(c, buff);
       SET_BIT(buff[0]);
       }
-    else SET_BIT(c);    
+    else if (c < 256) SET_BIT(c);    
 #else  /* 16-bit or 32-bit mode */
     if (c > 0xff) SET_BIT(0xff); else SET_BIT(c);
 #endif
diff --git a/testdata/testinput5 b/testdata/testinput5
index d90b66d..b3fcfef 100644
--- a/testdata/testinput5
+++ b/testdata/testinput5
@@ -2179,4 +2179,6 @@
 
 /\p{Any}*xyz/I
 
+/(|ß)7/caseless,ucp
+
 # End of testinput5
diff --git a/testdata/testoutput5 b/testdata/testoutput5
index ecf01fb..5bdf873 100644
--- a/testdata/testoutput5
+++ b/testdata/testoutput5
@@ -4938,4 +4938,6 @@ Overall options: anchored
 Last code unit = 'z'
 Subject length lower bound = 3
 
+/(|ß)7/caseless,ucp
+
 # End of testinput5