Siege Blueprints Case cant be compacted
You could always open them, and stack the Blueprints within. /shrug
Good luck.
Are you complaining that they don’t stack or don’t compact, as in auto-change position when directed to do so?
Because, in spite of everyone of those containers share the same name, have different ID’s.
Same happens with other containers like Champion’s Bags or Boxes.
Have fun and good luck.
Note: I am assuming you are talking about “stacking”.