Migration database schema: explode() error occurred

Your software
My Mautic version is:v3.1.0
My PHP version is: 7.3.21

Your problem
My problem is:
After upgrading from v.3.0.2(new installed) to v.3.1.0, I can’t migrate the database schema.
These errors are showing in the log:
php bin/console mautic:update:apply --update-package=~/webapps/mauticapp/3.1.0-update.zip
Are you sure you wish to update Mautic to the latest version? yes

The ZIP archive could not be found.
You have new mail in /var/mail/mauticuser
mauticuser@ip-172-26-11-254:~/webapps/mauticapp$ php bin/console mautic:update:apply --update-package=3.1.0-update.zip
Are you sure you wish to update Mautic to the latest version? yes
Step 4 [---->-----------------------] Clearing the cache

IMPORTANT: Run the same command again with --finish. For example ‘php bin/console mautic:update:apply --finish’
mauticuser@ip-172-26-11-254:~/webapps/mauticapp$ php bin/console mautic:update:apply --update-package=3.1.0-update.zip --finish
Step 1 [->--------------------------] Migrating database schema…
In Version20200422144300.php line 115:

Type error: explode() expects parameter 2 to be string, array given

mautic:update:apply [–force] [-p|–update-package [UPDATE-PACKAGE]] [–finish] [-h|–help] [-q|–quiet] [-v|vv|vvv|–verbose] [-V|–version] [–ansi] [–no-ansi] [-n|–no-interaction] [-e|–env ENV] [–no-debug] [–]
Steps I have tried to fix the problem:
Step. enter the following command:
php bin/console doctrine:migration:migrate

Your database version (5.5.5-10.4.14-MariaDB-1:10.4.14+maria~bionic-log) does not support generated columns. Upgrade at least to 10.2.6 and update db_server_version accordingly to get the speed improvements.

                Mautic Migrations                    

WARNING! You are about to execute a database migration that could result in schema changes and data loss. Are you sure you wish to continue? (y/n)y
Migrating up to 20200815153711 from 20200302164801

++ migrating 20200422144300 (Migrate mautic_lead_fields.properties to simple array)

Migration 20200422144300 failed during Execution. Error explode() expects parameter 2 to be string, array given

In Version20200422144300.php line 115:

Type error: explode() expects parameter 2 to be string, array given

doctrine:migrations:migrate [–write-sql [WRITE-SQL]] [–dry-run] [–query-time] [–allow-no-migration] [–all-or-nothing [ALL-OR-NOTHING]] [–configuration [CONFIGURATION]] [–db-configuration [DB-CONFIGURATION]] [–db DB] [–em EM] [–shard SHARD] [-h|–help] [-q|–quiet] [-v|vv|vvv|–verbose] [-V|–version] [–ansi] [–no-ansi] [-n|–no-interaction] [-e|–env ENV] [–no-debug] [–] []

Here is what I did (no idea what the long term effect is, but mautic works for now.)

EDIT
app/migrations/Version20200422144300.php
Change line 115 from
$propertyList = explode('|', $properties['list']);
to
$propertyList = $properties['list'];

Good luck.