bento/ubuntu-24.04 claiming it doesn't support requested provider

[thecommonthread]

I'm running virtualbox 7.2.4 with a fresh download of bento/ubuntu24.04 on Windows 11 Home with Intel Core 7 240H processor. It keeps telling me that virtualbox isn't supported.

> vagrant up --provision --provider=virtualbox
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Box 'bento/ubuntu-24.04' could not be found. Attempting to find and install...
    default: Box Provider: virtualbox
    default: Box Version: >= 0
==> default: Loading metadata for box 'bento/ubuntu-24.04'
    default: URL: https://vagrantcloud.com/api/v2/vagrant/bento/ubuntu-24.04
The box you're attempting to add doesn't support the provider
you requested. Please find an alternate box or use an alternate
provider. Double-check your requested provider to verify you didn't
simply misspell it.

If you're adding a box from HashiCorp's Vagrant Public Registry, make sure the box is
released.

Name: bento/ubuntu-24.04
Address: https://vagrantcloud.com/api/v2/vagrant/bento/ubuntu-24.04
Requested provider: virtualbox

If I try to add the box with a general command, it fails:

> vagrant box add bento/ubuntu-24.04
==> box: Loading metadata for box 'bento/ubuntu-24.04'
    box: URL: https://vagrantcloud.com/api/v2/vagrant/bento/ubuntu-24.04
The box you're attempting to add has no available version that
matches the constraints you requested. Please double-check your
settings. Also verify that if you specified version constraints,
that the provider you wish to use is available for these constraints.

Box: bento/ubuntu-24.04
Address: https://vagrantcloud.com/api/v2/vagrant/bento/ubuntu-24.04
Constraints: >= 0
Available versions:

If I add flags to the command, it is successful:

> vagrant box add bento/ubuntu-24.04 --provider=virtualbox --architecture=amd64
==> box: Loading metadata for box 'bento/ubuntu-24.04'
    box: URL: https://vagrantcloud.com/api/v2/vagrant/bento/ubuntu-24.04
==> box: Adding box 'bento/ubuntu-24.04' (v202510.26.0) for provider: virtualbox (amd64)
    box: Downloading: https://vagrantcloud.com/bento/boxes/ubuntu-24.04/versions/202510.26.0/providers/virtualbox/amd64/vagrant.box
==> box: Box download is resuming from prior download progress
    box:
==> box: Successfully added box 'bento/ubuntu-24.04' (v202510.26.0) for 'virtualbox (amd64)'!

But I still can't vagrant up, telling me it doesn't support the provider. I'm clearly on a supported CPU.