Warning messages on portfolio pages

Polylang is using WordPress filters that send 5 parameters : https://developer.wordpress.org/reference/hooks/get_adjacent_post_join/ and https://developer.wordpress.org/reference/hooks/get_adjacent_post_where/ so it expects 5 parameters but don’t receive them all. That’s why tou get warnings.
The only explanation that I can provide is that your theme or a 3rd party plugin is applying the same filters than WordPress but with less parameters than WordPress, which is wrong.
I suggest that you deactivate them one by one until the warnings disappear. This will help you find the culprit an report the bug.
Additionnally once you have found the conflict source, I suggest that you define your WP_DEBUG to false in your wp-config.php. The warnings are not meant to be displayed on production sites.

In this case, they should not appear. At least I never encountered such case. I suggest that you contact your host provider and ask them why PHP warnings are displayed although your WP_DEBUG is set to false.