Packer to vagrant disk size is changing

I’m working on creating Virtualbox VMs and I’m not getting the expected disk size. It seems to change once I start it with Vagrant.

I build a box with Packer. My packer config is here: { "builders": [ { "name": "ubuntu-2004", "type": " -
packer build ubuntu20.json

Here’s a screenshot of Virtualbox as packer is doing its work. As expected the disk is as defined in disk_size of 7000:

I do a vagrant up and this is what I get. The size of the disk has changed to what Packer defines as default, 40000:

Interestingly enough, this seems to be occuring on one VirtualBox host but not another. Although this may ultimately be a VB issue, can anyone here offer insight as to what might be causing this?