pt-osc --alter-foreign-keys-method=drop_swap doesn't work with MariaDB 10.x (PT 3.3.1)

Hello,

Recently noticed that ps-osc fails with MariaDB 10.x.  It throws the same error as if one was running MySQL 8.0:

Running MariaDB 10.2.17.

Just upgraded to Percona Toolkit 3.0.12-1.el6.

Ran:

pt-online-schema-change --user=root --password=********** --execute --alter-foreign-keys-method=auto --alter "MODIFY ..." D=xxxxx,t=yyyyy,h=localhost

Output:

No slaves found. See --recursion-method if host hostnameXYZ has slaves.
Not checking slave lag because no slaves were found and --check-slave-lag was not specified.
Operation, tries, wait:
analyze_table, 10, 1
copy_rows, 10, 0.25
create_triggers, 10, 1
drop_triggers, 10, 1
swap_tables, 10, 1
update_foreign_keys, 10, 1
Child tables:
`xxxxx`.`t1` (approx. 1511207 rows)
`xxxxx`.`t2` (approx. 147803 rows)
`xxxxx`.`t3` (approx. 401 rows)
`xxxxx`.`t4` (approx. 2015760 rows)
Will automatically choose the method to update foreign keys.
Altering `xxxxx`.`yyyyy`...
Creating new table...
Created new table xxxxx._yyyyy_new OK.
Altering new table...
Altered `xxxxx`.`_yyyyy_new` OK.
2018-11-02T14:42:25 Creating triggers...
2018-11-02T14:42:25 Created triggers OK.
2018-11-02T14:42:25 Copying approximately 1168528 rows...
Copying `xxxxx`.`yyyyy`: 68% 00:13 remain
2018-11-02T14:43:33 Copied rows OK.
2018-11-02T14:43:33 Max rows for the rebuild_constraints method: 46038
Determining the method to update foreign keys...
2018-11-02T14:43:33 `xxxxx`.`t1`: too many rows: 1511207; must use drop_swap
2018-11-02T14:43:33 Dropping triggers...
2018-11-02T14:43:34 Dropped triggers OK.
Not dropping the new table `xxxxx`.`_yyyyy_new` because --swap-tables failed. To drop the new table, execute:
DROP TABLE IF EXISTS `xxxxx`.`_yyyyy_new`;
`xxxxx`.`yyyyy` was not altered.
--alter-foreign-keys-method=drop_swap doesn't work with MySQL 8.0+
See https://bugs.mysql.com/bug.php?id=89441 at /usr/bin/pt-online-schema-change line 9823.

This seems somewhat related to:

https://bugs.mysql.com/bug.php?id=89441
https://jira.percona.com/browse/PT-1569

However, it seems that the version is being read wrong, or being confused with MySQL 8.0.

Current work-around is to run with: --alter-foreign-keys-method=rebuild_constraints

Thank you.