diff --git a/include/spdlog/pattern_formatter-inl.h b/include/spdlog/pattern_formatter-inl.h
index e68b91be4..3726a8774 100644
--- a/include/spdlog/pattern_formatter-inl.h
+++ b/include/spdlog/pattern_formatter-inl.h
@@ -1246,9 +1246,24 @@ SPDLOG_INLINE void pattern_formatter::handle_flag_(char flag, details::padding_i
 
     default: // Unknown flag appears as is
         auto unknown_flag = details::make_unique<details::aggregate_formatter>();
-        unknown_flag->add_ch('%');
-        unknown_flag->add_ch(flag);
-        formatters_.push_back((std::move(unknown_flag)));
+
+        if (!padding.truncate_)
+        {
+            unknown_flag->add_ch('%');
+            unknown_flag->add_ch(flag);
+            formatters_.push_back((std::move(unknown_flag)));
+        }
+        // fix issue #1617 (prev char was '!' and should have been treated as funcname flag instead of truncating flag)
+        // spdlog::set_pattern("[%10!] %v") => "[      main] some message"
+        // spdlog::set_pattern("[%3!!] %v") => "[mai] some message"
+        else
+        {
+            padding.truncate_ = false;
+            formatters_.push_back(details::make_unique<details::source_funcname_formatter<Padder>>(padding));
+            unknown_flag->add_ch(flag);
+            formatters_.push_back((std::move(unknown_flag)));
+        }
+
         break;
     }
 }
diff --git a/tests/test_pattern_formatter.cpp b/tests/test_pattern_formatter.cpp
index 848398fd3..944929298 100644
--- a/tests/test_pattern_formatter.cpp
+++ b/tests/test_pattern_formatter.cpp
@@ -227,7 +227,7 @@ TEST_CASE("paddinng_truncate", "[pattern_formatter]")
     REQUIRE(log_to_str("123456", "%0!v", spdlog::pattern_time_type::local, "\n") == "\n");
 }
 
-TEST_CASE("paddinng_truncate_funcname", "[pattern_formatter]")
+TEST_CASE("padding_truncate_funcname", "[pattern_formatter]")
 {
     spdlog::sinks::test_sink_st test_sink;
 
@@ -237,13 +237,28 @@ TEST_CASE("paddinng_truncate_funcname", "[pattern_formatter]")
 
     spdlog::details::log_msg msg1{spdlog::source_loc{"ignored", 1, "func"}, "test_logger", spdlog::level::info, "message"};
     test_sink.log(msg1);
+    REQUIRE(test_sink.lines()[0] == "message [ func]");
 
     spdlog::details::log_msg msg2{spdlog::source_loc{"ignored", 1, "function"}, "test_logger", spdlog::level::info, "message"};
     test_sink.log(msg2);
+    REQUIRE(test_sink.lines()[1] == "message [funct]");
+}
+
+TEST_CASE("padding_funcname", "[pattern_formatter]")
+{
+    spdlog::sinks::test_sink_st test_sink;
 
-    auto lines = test_sink.lines();
-    REQUIRE(lines[0] == "message [ func]");
-    REQUIRE(lines[1] == "message [funct]");
+    const char *pattern = "%v [%10!]";
+    auto formatter = std::unique_ptr<spdlog::formatter>(new spdlog::pattern_formatter(pattern));
+    test_sink.set_formatter(std::move(formatter));
+
+    spdlog::details::log_msg msg1{spdlog::source_loc{"ignored", 1, "func"}, "test_logger", spdlog::level::info, "message"};
+    test_sink.log(msg1);
+    REQUIRE(test_sink.lines()[0] == "message [      func]");
+
+    spdlog::details::log_msg msg2{spdlog::source_loc{"ignored", 1, "func567890123"}, "test_logger", spdlog::level::info, "message"};
+    test_sink.log(msg2);
+    REQUIRE(test_sink.lines()[1] == "message [func567890123]");
 }
 
 TEST_CASE("clone-default-formatter", "[pattern_formatter]")