yum not updating dependency during install

I have a situation where my-software requires my-common via:

Requires: my-common >= 1.2.0

During yum update my-software, my-common is not upgraded, and is left at version 0.0.1.

Why is yum not updating my-common -- and the install of my-software completes without error, even though the dependency for my-common is not resolved?

See:

# yum deplist my-software
package: my-software.noarch 1.1.0-1637255366
  dependency: /bin/sh
   provider: bash.x86_64 4.2.46-34.el7
  dependency: my-common >= 1.2.0
   provider: my-common.x86_64 1.2.0-1637243847.el7_9
   provider: my-common.noarch 0.0.1-20180703160841.el7

Note that yum thinks that my-common is resolved by either of:

• my-common.x86_64 1.2.0-1637243847.el7_9
• my-common.noarch 0.0.1-20180703160841.el7

The latter is already installed. Running yum update my-common correctly updates to the 1.2.0 version, and then my-software works correctly.

Noting that the timestamp in the latter package is incorrectly formatted and appears "newer" than the first. But the first has the version I'm requiring, so I would have expected the latter to be completely excluded from the list of valid packages.