CiviMail adding ?civiwp=CiviCRM to all links - causing links to be bad
You are correct.  That is a bug.  here is the report - https://lab.civicrm.org/dev/core/-/issues/1865
It's been fixed https://github.com/civicrm/civicrm-core/commit/bcbfa93e255ee15d9bd9e0f812b2a5a617458d73  and is planned for the next 5.27 release