Secondary monitor flickers after Windows 10 update (when using PowerPoint)

Question

Background:

• Asus PC (circa 2015) running Windows 10, PowerPoint 2010
• AMD Radeon graphics card (model unknown at this writing)
• Second monitor is really a splitter to a projector and wide-screen TV (this is A/V system in a church setting)
• A similar problem (below) had been addressed by disabling EDID via the AMD Catalyst Control Center, but since a recent Windows 10 update, the problem has returned and disabling is not available.

Problem:

• During auto-advance in PowerPoint, the system starts to flicker as though hunting for proper resolution.
• At other times, the display on the "secondary monitor" (i.e. projector and wide-screen) will go to 25%. The desktop monitor image is full screen, but the resolution has changed.

Question:

• Research has shown a registry hack to disable EDID, but we are uncomfortable with this solution.
• Is there another fix, either via AMD Catalyst Control Center, or otherwise? E.g. If it is a problem with the wide-screen TV, is there a way to permanently set the desired resolution (either on the TV or the PC)?