Variations are broken. How to fix the error?

Question

Online shopping

Good afternoon colleagues.
We have a door store on Wordpress 4.61 and WooCommerce 2.6.9
Each product had variations, but at one point an error appeared on the page with any product
Warning: array_unique() expects parameter 1 to be array, object given in .../wp-content /plugins/woocommerce/includes/class-wc-product-variable.php on line 422 (
line says $variation_attributes[ $attribute['name'] ] = array_unique( $values ​​); )
contain empty fields. As if some kind of damage to the base...
hoster nic.ru base innodb. Restoring from a 5-day backup did not bring any results to either the database or the site. (maybe there was a problem then)
An internet search showed that I'm not the only one with this problem, but I did not find a solution.
Tell me, do you have any good ideas? Thank you very much!

Answer 1

dzadoor.ru/product/%D0%B4%D0%B2%D0%B5%D1%80%D1%8C-d1...

Answer 2

Here they write that this is a problem of one of the plugins (not woo). https://github.com/woocommerce/woocommerce/issues/12052
And here a person writes that the problem was in the plugin in the Wordpress SEO plugin: https://wordpress.org/support/topic/261-getting-er.. I personally will still bet on a
crookedly written topic or on updating the PHP / MySQL version at the hoster - perhaps one of your plugins (or theme) is written according to the old version of PHP, and after updating the PHP hoster to the current version, the syntax of one of the functions of one of your plugins.
The solution is to start by updating WordPress, the theme and all plugins to the latest versions. If the problem persists, disable all plugins one by one and check if the error is gone. If it still does not go away - temporarily change the theme to the standard WordPress one and check if the error appears.