Season resets when making changes on a planned match

[Blenetic]

when i change something on a planned match, like say add/delete players who are attending the match the season gets set to a -
when i save the changes. the problem is that it also deletes the entry in the shared calendar i made for the team. I always have to manually select the correct season again.

[savvasha]

It seems like a Max Input Vars issue:
https://nichetwins.com/how-to-increase-max-input-vars-in-wordpress/

[Blenetic]

It seems like a Max Input Vars issue: https://nichetwins.com/how-to-increase-max-input-vars-in-wordpress/

the solution did not resolve the issue, i get a php warning now:

AH01071: Got error 'PHP message: PHP Warning: Array to string conversion in /var/www/fcpomerans.be/fcpomerans.be/wwwroot/wp-includes/formatting.php on line 1098', referer: https://fcpomerans.be/wp-admin/edit.php?post_type=sp_event