Dear Neville,
Contested minhagim from White Russia.
The three are:
1) Skipping shalosh seudos
2) Eating before shacharis
3) Not sleeping in the succah
They all had their rationales that aren’t so relevant today.
But people tend to keep their minhagim.
So I don’t see what the issue is.
Because it’s not just Chabad that does these things.