Steps to reproduce :
(1 to 5 are just there to outline the 'expected' behaviour)
1 - Define a text field - mark it multiple / NOT required
2 - Create a node with 3 values 'foo', 'bar' and 'baz' for the field
3 - Submit
4 - Edit the node, empty the first value 'foo'
5 - Submit : everything OK, the field has the values 'bar' and 'baz', and if you edit the node, you get 'bar' and 'baz' in the first and second textfields (values have shifted)
6 - Now set your field to REQUIRED
7 - Edit the node, empty the first value 'bar'
8 - Submit : you get a 'field is required' error on the first (empty) textfield, yet the field itself should not be considered empty, since you have the 'baz' value in the second textfield
This is content.module stuff - you get the behaviour with number, or noderef with autocomplete fields.
Closed: duplicate
8.9 ⚰️
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
The issue that this is marked as a duplicate of is not really this same problem. It is about a UI widget to let users remove items from a multiple value field. I added a new issue 🐛 Improve required validation of multiple value fields Active that is about improving 'required' validation of multiple value fields, to consider the field as a whole instead of only delta 0 in whatever position it might be.