diff --git a/grep.c b/grep.c
index 82eb7da102..b9553ec9f5 100644
--- a/grep.c
+++ b/grep.c
@@ -297,7 +297,9 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt
 
 #ifndef GIT_PCRE2_VERSION_10_36_OR_HIGHER
 	/* Work around https://bugs.exim.org/show_bug.cgi?id=2642 fixed in 10.36 */
-	if (PCRE2_MATCH_INVALID_UTF && options & (PCRE2_UTF | PCRE2_CASELESS))
+	if (PCRE2_MATCH_INVALID_UTF &&
+	    ((options & (PCRE2_UTF | PCRE2_CASELESS)) ==
+	     (PCRE2_UTF | PCRE2_CASELESS)))
 		options |= PCRE2_NO_START_OPTIMIZE;
 #endif