During the last week or so Microsoft Launcher has been defaulting the search engine to Bing randomly. I cannot determine the trigger that causes this behaviour. Even after a few app updates it still happens.
The good news is that since the update on 10/28, the Search Engine in the launcher preferences stays set to Google. The bad news is that searching still occasionally loads Bing anyway.
Extra info which may or may not be useful: This happens less often than before the update (i.e. it stays set to Google for a few days now, rather than changing back once a day or so). Before the update, the Search Engine setting was changing to Bing when the problem occurred; now it always says Google (but still sometimes incorrectly opens Bing). Changing this setting to something else and then back to Google restores expected behavior. I generally search through a gesture (double-tap) as opposed to the search widget. Default browser is Edge, with default search engine set to Google in Edge preferences. Android 11 running on Pixel 3 XL. Launcher version 6.2.201003.92174. I am in the Beta program.