Column level GRANT does not work correctly when table contains and SYSTEM_INVISIBLE or COMPLETELY_INVISIBLE column.
Suppose a table t1 , which has a SYSTEM_INVISIBLE column and a normal column A. We give a grant to user_1 with this command

grant insert(a) on t1 to user_1;

when this particular user try insert

insert into t1(a) values(1);

or

insert into t1 values(1);

he will get access denied error.