Deadlock with vBulletin server and replication

I have a vBulletin server running (v4.2.5), with PHP 7.1. They were running on the 10.1 version from the apt repositories from Debian (mariadb-server-core-10.1/stable 10.1.38-0+deb9u1).

I decided to upgrade the MariaDB using the MariaDB apt repo, which gave me an upgrade to 10.3.14.

The database is replicated onto another server with the same OS / MariaDB version from stratch (Debian 9 / MariaDB 10.3).

Replication works fine :

MariaDB [(none)]> show slave status \G

*************************** 1. row ***************************

                Slave_IO_State: Waiting for master to send event

                   Master_User: replication_user

                 Connect_Retry: 10

               Master_Log_File: master1-bin.000319

               Read_Master_Log_Pos: 56225430

                 Relay_Log_Pos: 56223609

            Relay_Master_Log_File: master1-bin.000319

              Slave_IO_Running: Yes

             Slave_SQL_Running: Yes

Now, whenever someone opens multiple threads in a very short time range, they will likely be facing a "Database error". As an admin, I can see what the error is, and I can guarantee that this wasn't present when the database used was MariaDB 10.1.

I opened a thread on the vBulletin support, but they told me there shouldn't be any issues on this type from the version I'm using, and they don't test every MariaDB version so they can't confirm the problem.

Is any help possible here ?

Here is the error I'm getting when it occurs :

Invalid SQL:

REPLACE INTO forum_ipdata

    (rectype, userid, contentid, contenttypeid, dateline, ip, altip)

VALUES

    ('view', 13574, 121872, 2, 1556868134, '82.64.xxx.xxx', '82.64.xxx.xxx');

MySQL Error   : Deadlock found when trying to get lock; try restarting transaction

Error Number  : 1213

Request Date  : Friday, May 3rd 2019 @ 09:22:14 AM

Error Date    : Friday, May 3rd 2019 @ 09:22:15 AM

Script        : http://mysuperforum/threads/123456-any-thread

Referrer      : 

IP Address    : xx.xx.xx.xx

Username      : Wobak

Classname     : vB_Database_MySQLi

MySQL Version : 10.3.14-MariaDB-1:10.3.14+maria~stretch-log

Server        :  xx.xx.xxx.xx

User Agent    :

(I masked the IPs)

Tables are running in InnoDB for almost all the tables (the issue also occured when they were in MyISAM).

Could this be due to replication ?
Is there anything I can provide to help fix this ?

Thanks,