[BUG] - Boolean fields display [object object] with Next.js 15.4+

[vincentwinkel]

Description

This is the (simplified) code:

        createdAt: { formatter: (date) => <span>test</span> },
        isPrivate: { formatter: (bool) => <span>test</span> },

And the result. It looks like the boolean field is broken:

Reproduction URL

null

Reproduction steps

1. I used nextjs 15.2 and nextAdmin 8.1.4, all working perfectly.
2. Then I upgraded to nextjs 15.4, and I noticed an issue on the `formatter` function.
3. I upgraded nextAdmin to 8.3.0 but still the same issue.

Next router

App router

Next Admin version

8.1.4 then 8.3.0

Screenshots

Next Admin options

Logs

Browsers

Chrome

[vincentwinkel]

The same issue seems to occur fot Json fields as well.

[vincentwinkel]

I confirm that there is no issue with nextjs 15.3 (only 15.4).