I loaded LR, PS, and AI, then moved them from primary monitor (in upright format) to a secondary monitor (which is in landscape format), maximise them, close them. Next time I open them, they always remember to load to the same place as before, namely the second monitor.

But InDesign keeps loading in the primary monitor, I have to keep shifting it over to the secondary monitor every time I start InDesign.

Seeking the forum for answers, I noticed someone already asked that question, why do it keeps opening in primary window, and it was posted around 2015 or thereabouts.

Have you not actually fixed this bug? Nearly all other software (Adobe, Microsoft, LR, PS, AI, IE, Windows, any application), always load to last monitor used, yet InDesign seems to always start back on the first monitor.