According to the CMSIS-Pack 1.6.0 specification the version number for a required pack is optional, but leaving it out causes the plugin to attempt to install the required pack in the same version as the pack being installed.

Example:
Maxim.MAX32650.pdsc contains the following pieces:

  <release version="1.1.0-a" date="2018-07-11">
     - Updates to ARM startup
  </release>

...




...

Installing this pack causes the plugin to attempt to install ARM.CMSIS.1.1.0-a, which seems wrong.

If a version number is available for the requirement then that version is used, which is the expected behavior.