Lost one scavenger bot when I started a New Game+ at 'Impossible' difficulty - How do I fix or avoid this?

After finishing the game with a total of three scavenger bots, I started a New Game+ at 'Impossible' difficulty. However, I only got two scavenger bots at the start.

I already got to the part of the game where I get my "first" scavenger bot if in a New Game (Chapter 5), but I still had a total of two scavenger bots after that.

Is this by design if playing at 'Impossible' difficulty or is it a bug? If by design, will I get another scavenger bot at a later part of the game? If it's a bug, how do I avoid it when starting a New Game+? And is there a way to fix it?

EDIT:
There are speculations that this is a bug and is caused by not collecting all scavenger bots before finishing the game: [1] [2]. Anyone know where the last bench accessible in the game is (so the player won't drop a scavenger bot after retrieving all bots from that last bench, avoiding this bug)? Does anyone know if restarting a chapter from a finished New Game save may somehow fix this?

I believe this is a bug, I have had the same thing happen to me and have heard from others who have lost 2 or even all three of their scavenger bots. they supposedly lost them from not having all three retreived when they started a new game+