I really don't understand your reasoning. Let me clarify the scenario: 1. the user modified the default application for PDF to use FoxIt. 2. Win10 reverts th

I really don't understand your reasoning. Let me clarify the scenario: 1. the user modified the default application for PDF to use FoxIt. 2. Win10 reverts the assignment back to Edge after an update and/or reboot. There is no other program involved. There is a user setting the preference and Win10 ignoring it, consistently for a period of several years, ever since I installed it.