diff --git a/mysql-test/suite/multi_source/disabled.def b/mysql-test/suite/multi_source/disabled.def
index 45c8a6c8891..e69de29bb2d 100644
--- a/mysql-test/suite/multi_source/disabled.def
+++ b/mysql-test/suite/multi_source/disabled.def
@@ -1 +0,0 @@
-mdev-8874 : MDEV-20101 Assertion failure
diff --git a/mysql-test/suite/sys_vars/r/replicate_ignore_table_basic.result b/mysql-test/suite/sys_vars/r/replicate_ignore_table_basic.result
index db97ce14c93..a1701635f0e 100644
--- a/mysql-test/suite/sys_vars/r/replicate_ignore_table_basic.result
+++ b/mysql-test/suite/sys_vars/r/replicate_ignore_table_basic.result
@@ -46,3 +46,13 @@ SELECT @@GLOBAL.replicate_ignore_table;
 
 # Cleanup.
 SET @@GLOBAL.replicate_ignore_table = @save_replicate_ignore_table;
+#
+# MDEV-20101 Assertion failure on select @@global.'m2'.replicate_ignore_table
+#
+SET NAMES latin1;
+SELECT @@global.'m2'.replicate_ignore_table;
+@@global.'m2'.replicate_ignore_table
+NULL
+Warnings:
+Warning	1617	There is no master connection 'm2'
+Warning	1617	There is no master connection 'm2'
diff --git a/mysql-test/suite/sys_vars/t/replicate_ignore_table_basic.test b/mysql-test/suite/sys_vars/t/replicate_ignore_table_basic.test
index 56cf7f17c7f..1cf6f010eca 100644
--- a/mysql-test/suite/sys_vars/t/replicate_ignore_table_basic.test
+++ b/mysql-test/suite/sys_vars/t/replicate_ignore_table_basic.test
@@ -49,3 +49,10 @@ SELECT @@GLOBAL.replicate_ignore_table;
 
 --echo # Cleanup.
 SET @@GLOBAL.replicate_ignore_table = @save_replicate_ignore_table;
+
+--echo #
+--echo # MDEV-20101 Assertion failure on select @@global.'m2'.replicate_ignore_table
+--echo #
+
+SET NAMES latin1;
+SELECT @@global.'m2'.replicate_ignore_table;
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index fafac28cf8e..0e6fe2a0c51 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -2400,7 +2400,6 @@ bool THD::check_string_for_wellformedness(const char *str,
                                           size_t length,
                                           CHARSET_INFO *cs) const
 {
-  DBUG_ASSERT(charset_is_system_charset);
   size_t wlen= Well_formed_prefix(cs, str, length).length();
   if (wlen < length)
   {