I’ve seen claims that this is for structural reinforcement of sandbags, which makes no sense on multiple levels. (Even if the tank armour can’t resist bullets, a premise which raises its own host of questions, there is better light armour. And even if one insists on sand, a requirement which raises its own host of questions, civil engineering has better solved the problem of immobilising sand.) Those claims also have zero history before photos of the egg cartons emerged, which isn’t unexpected for military kit, but suspect given Moscow’s tendency for ham-fisted retconning.

The broader point is, whether designed that way or not, it’s evidence of incompetence. If the people doing that built a pipe part, I wouldn’t be surprised to see it fail. (Though based on German comments, there is reason to suspect foul play.)