Hey mbi, I was out of the office for a few days so I have not investigated this fully, but I did find one thing that fixed my issue. I do not know if it will help your situation, but is something to consider.
The order of the DNS servers I had listed seemed to create the problem for me (I haven't looked into why yet).
The following order of DNS servers DID cause this package update issue.
internal lan dns server
isp dns server 1
isp dns server 2
google dns server
The following order immediately resolved the package update issue.
isp dns server 1
isp dns server 2
google dns server
internal lan dns server
So for me, just moving my internal lan dns server to the bottom of the list made the error go away. I tested this back and forth a couple of times to make sure it was the only change I made to resolve my issue. As I mentioned, I haven't investigated this further to understand why, and the rest of my configuration may be way different from yours. But it may give you help.
Jeff