Hi I've contacted 2 mods developers about an infinite loop that seems to have been narrowed down to this mod, the linked discussions are as folow.
Better Robots Extended and Blueprint Sandboxes Hope I could help out

Thanks,
Wanderer

Hello LeWanderer,

Thanks for reporting the bug, I will try to first reproduce it locally to figure out why it happens. If I end up having issues around that, it could be useful if you can also provide me with (reliable-ish) reproduction steps (I will try to follow some of the steps that Nick1Z2 pointed out) to ease the process. :)

Best regards,
Branko

I was able to reproduce the issue with your savegame, so at least I should be able to both fix the thing and test it.

On the other hand... What I found interesting is I could not produce this problem with just the Blueprint Sandboxes, Better Robots Extended, and Construction Approvals - either in a new game, or just loading up your current game with only these three mods enabled.

Best regards,
Branko

Hello LeWanderer,

I have just released 5.1.1 bugfix release that should address your problem. There is some kind of chance of a desync between researched technologies between the unapproved ghosts and player's main force (can result in not having the same set of machine recipes available), but I can try to go for something more complicated should that become an issue.

If you can give it a quick test and let me know if it solves the issue for you, that would be great. :)

Best regards,
Branko