[6.x]: Fields retain values when cleared

[DenyEs]

What happened?

Description

I noticed I can't remove values off of populated fields. I tried it with Plain Text field and even created a new one to rule out the "replica" fields but still the same issue. "entries" field does the same thing. Replacing with different text or different related entry works, it seems to have an issue with empty values.

Steps to reproduce

1. Create a new plain text field
2. Assign to an entry type
3. Fill in a value and save an entry
4. Try to remove the value

Expected behavior

Field becomes empty.

Actual behavior

Field contains the old value.

Craft CMS version

6.0.0-alpha3

PHP version

8.5

Operating system and version

macOS 26.5

Database type and version

MySQL 8.4.6

Image driver and version

No response

Installed plugins and versions

No response

[linear-code]

CMS-2102