If you switch to another application, while InDesign is launching, InDesign will steal the focus back, even repeatedly if you are quick enough to switch to the other application more than once, and/or have a slow computer (e.g. battery saver mode while opening a large document may exaggerate the problem).

I'm fairly certain that this irritating behaviour was gone from late 2017, since the earlier bug report (https://indesign.uservoice.com/forums/601180-adobe-indesign-bugs/suggestions/31913773-indesign-steals-focus-in-windows-10) was closed after lack of activity (3 years old) in 2021, and the old thread on the forum https://community.adobe.com/t5/indesign-discussions/how-to-prevent-adobe-software-stealing-focus-in-windows-10-locked/td-p/7773884/page/5 was active until late 2017. At Nov 17th 2017 users edvardkrupke and Peter Bullit wrote that the problem was gone with the latest InDesign update at that time.

Please remove this very unwanted behaviour (again)!