vagrant up: Got different reports about installed GuestAdditions version

Possibly too late for OP but in case it helps anyone else, comments in the vagrant-vbguest plugin project on GitHub suggest the additions are installed correctly but reported incorrectly. Updating to the latest version fixed it for me:

vagrant plugin update
Updating installed plugins...
Updated 'vagrant-vbguest' to version '0.14.2'!

I've found a working solution. Add the following code to your Vagrantfile somewhere in the Vagrant.configure("2") do |config| section.

if Vagrant.has_plugin? "vagrant-vbguest"
  config.vbguest.no_install  = true
  config.vbguest.auto_update = false
  config.vbguest.no_remote   = true
end

I had same issue on Ubuntu 18.04 with Virtualbox 5.2.18

Fix: add the following lines to your vagrant file.

if Vagrant.has_plugin?("vagrant-vbguest")
    config.vbguest.auto_update = false  
end

See this comment at github