After installing the optional Cumulative Update released on 24 March 2020, we found two breaking issues:
that sites added to the Enterprise Mode Site List were opening in multiple tabs. When accessing the new site, Edge created multiple tabs, causing Edge to use 100% of the CPU until the Edge process was killed. Sometimes only a reboot stopped the creation of tabs.
shortcuts in the Start menu to Internet Explorer with target to an internal application opened in Edge. Up until the installation of the CU, these sites opened in full Internet Explorer.
No mitigation was found for these issues. Only resolution was to remove the CU.
This CU is a precursor to the official April CU.
Our systems at the time: Edge 80.0.361.111 Windows 1909