Comment 5 for bug 1766161

I can reproduce this so I'll mark the report as affecting me too.

1) Open synaptic and identify one or more packages that are not to be upgraded
2) Mark them with "Lock version" - they get shown as "Pinned"
3) Close synaptic
4) Add PPA that would provide an update to those packages
5) Reload packages in synaptic to verify packages pinned correctly
4) In a terminal run "sudo apt update" and "sudo apt upgrade" - packages are upgraded
5) Open synaptic
6) Packages are still shown as "Pinned" but against the updated version numbers

Not the best example I know but it does show that the pinning of packages in synaptic isn't recognised by running apt or apt-get commands in a terminal. I have a feeling that the opposite applies too. Holding packages with apt-mark doesn't stop synaptic from upgrading those packages.

This was tested with synaptic 0.84.3ubuntu1 in Ubuntu 18.10 (dev)