Description:
Table with update trigger containing a user defined function.
Doing an update on the table with a join produces the error "ERROR 1305 (42000): FUNCTION <db>.<fkt> does not exist".
Calling the function befor doing the update, the update is working.
Only on MariaDB 10.3.15, not in 10.3.14

Preconditions:
MariaDB 10.3.15 is installed from box.
Only information_schema, mysql and performance_schema are available after installation. No user databases are present.
All actions are performed with the user root.

SQL Steps to reproduce:
create database triggertest;
use triggertest;

create table tu (
ID integer not null default '0',
val integer not null default '0'
);

create table tc (
ID integer not null default '0',
val integer not null default '0'
);

delimiter //

create function addone(i integer) returns integer
deterministic
sql security invoker
begin
return i+1;
end//

create trigger tu_au after update on tu
for each row
begin
insert into tc (ID, val)
select NEW.ID, addone(NEW.val) from dual;
end//
delimiter ;

insert into tu (ID, val) values (1,1);

create temporary table t select 1 as ID;

update tu join t using(ID) set val = 2 where ID = 1;
– Error: ERROR 1305 (42000): FUNCTION triggertest.addone does not exist

select addone(1);

update tu join t using(ID) set val = 3 where ID = 1;
– no Error