Problem by setting new PHP version

I got the following problem by upgrading the PHP version from my website from PHP 7.4.9 to 8.0.13:

I get an error by adding or editing an item:  0 count(): Argument #1 ($value) must be of type Countable|array, null given

When downgrading the PHP version back to PHP 7.4.9 the problem is solved. Do you know how I can solve this problem?

hello you need to waiting a little we works on php8 o clean all message

Hi, I updated to Flexicontent version 4.1.3 (which should be php 8.x supportive), however the same error occured by adding or editing an item: 0 count(): Argument #1 ($value) must be of type Countable|array, null given

Hello Can you be more précise ?
Actived error reporting to max and say me where you have this error ?
Regards

When I click in the Flexicontent environment at the backend of my website on the button 'New', I select type 'Article' and then the error occur. The same error occur when I click on an article to edit it. Instead of opening the editor for that article, the error occur. With PHP 7.4 no error occurs and I can write or edit an article, but with PHP 8.0 and 8.1 the error occur.

See printscreen in attachment. 

1 please update to this version github.com/FLEXIcontent/flexicontent-cck...efs/heads/master.zip
2 actived error reporting to maximum and send me return