diff --git a/mysql-test/suite/innodb/r/instant_alter_crash.result b/mysql-test/suite/innodb/r/instant_alter_crash.result
index d15c0337c37..c16d5951c07 100644
--- a/mysql-test/suite/innodb/r/instant_alter_crash.result
+++ b/mysql-test/suite/innodb/r/instant_alter_crash.result
@@ -181,3 +181,27 @@ t3	CREATE TABLE `t3` (
 ) ENGINE=InnoDB DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
 DROP TABLE t1,t2,t3;
 db.opt
+#
+#  MDEV-26198 Assertion `0' failed in row_log_table_apply_op during
+#		ADD PRIMARY KEY or OPTIMIZE TABLE
+#
+CREATE TABLE t1(f1 year default null, f2 year default null,
+f3 text, f4 year default null, f5 year default null,
+f6 year default null, f7 year default null,
+f8 year default null)ENGINE=InnoDB ROW_FORMAT=REDUNDANT;
+INSERT INTO t1 VALUES(1, 1, 1, 1, 1, 1, 1, 1);
+ALTER TABLE t1 ADD COLUMN f9 year default null, ALGORITHM=INPLACE;
+set DEBUG_SYNC="row_log_table_apply1_before SIGNAL con1_insert WAIT_FOR con1_finish";
+ALTER TABLE t1 ROW_FORMAT=REDUNDANT, ADD COLUMN f10 YEAR DEFAULT NULL, ALGORITHM=INPLACE;
+connect con1,localhost,root,,,;
+SET DEBUG_SYNC="now WAIT_FOR con1_insert";
+INSERT IGNORE INTO t1 (f3) VALUES ( 'b' );
+INSERT IGNORE INTO t1 (f3) VALUES ( 'l' );
+SET DEBUG_SYNC="now SIGNAL con1_finish";
+connection default;
+disconnect con1;
+SET DEBUG_SYNC=RESET;
+CHECK TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	check	status	OK
+DROP TABLE t1;
diff --git a/mysql-test/suite/innodb/t/instant_alter_crash.test b/mysql-test/suite/innodb/t/instant_alter_crash.test
index 43db8f619f3..292de8a802b 100644
--- a/mysql-test/suite/innodb/t/instant_alter_crash.test
+++ b/mysql-test/suite/innodb/t/instant_alter_crash.test
@@ -205,3 +205,29 @@ DROP TABLE t1,t2,t3;
 
 --remove_files_wildcard $MYSQLD_DATADIR/test #sql*.frm
 --list_files $MYSQLD_DATADIR/test
+
+--echo #
+--echo #  MDEV-26198 Assertion `0' failed in row_log_table_apply_op during
+--echo #		ADD PRIMARY KEY or OPTIMIZE TABLE
+--echo #
+CREATE TABLE t1(f1 year default null, f2 year default null,
+                f3 text, f4 year default null, f5 year default null,
+		f6 year default null, f7 year default null,
+		f8 year default null)ENGINE=InnoDB ROW_FORMAT=REDUNDANT;
+INSERT INTO t1 VALUES(1, 1, 1, 1, 1, 1, 1, 1);
+ALTER TABLE t1 ADD COLUMN f9 year default null, ALGORITHM=INPLACE;
+set DEBUG_SYNC="row_log_table_apply1_before SIGNAL con1_insert WAIT_FOR con1_finish";
+send ALTER TABLE t1 ROW_FORMAT=REDUNDANT, ADD COLUMN f10 YEAR DEFAULT NULL, ALGORITHM=INPLACE;
+
+connect(con1,localhost,root,,,);
+SET DEBUG_SYNC="now WAIT_FOR con1_insert";
+INSERT IGNORE INTO t1 (f3) VALUES ( 'b' );
+INSERT IGNORE INTO t1 (f3) VALUES ( 'l' );
+SET DEBUG_SYNC="now SIGNAL con1_finish";
+
+connection default;
+reap;
+disconnect con1;
+SET DEBUG_SYNC=RESET;
+CHECK TABLE t1;
+DROP TABLE t1;
diff --git a/storage/innobase/rem/rem0rec.cc b/storage/innobase/rem/rem0rec.cc
index de300bf799a..3bb417eedff 100644
--- a/storage/innobase/rem/rem0rec.cc
+++ b/storage/innobase/rem/rem0rec.cc
@@ -287,7 +287,9 @@ rec_init_offsets_comp_ordinary(
 							 != n_core)
 		? UT_BITS_IN_BYTES(unsigned(index->get_n_nullable(n_core)))
 		: (redundant_temp
-		   ? UT_BITS_IN_BYTES(index->n_nullable)
+		   ? (index->is_instant()
+		      ? UT_BITS_IN_BYTES(index->get_n_nullable(n_core))
+		      : UT_BITS_IN_BYTES(index->n_nullable))
 		   : index->n_core_null_bytes);
 
 	if (mblob) {