Server 18.04 LTS no updates available for server B, but system A sees available updates at logon

I have two Dell Poweredge servers, each running server 18.04.3 LTS Server A’s kernel is 5.3.0-26-generic; Server B’s kernel is 4.15.0-74-generic. Each is nearly installation default plus similar Samba and NFS configurations. I start them every morning within seconds of each other and log on. A shows updates available fairly often, and many of them…

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