Why did Raymond shares dropped 66% from ₹1,500 apiece to ₹500 in a day?

The ex-date for a demerger is the date on which shares of the parent company start trading without the right to receive shares of the demerged (spun-off) company

Why did Raymond shares dropped 66% from ₹1,500 apiece to ₹500 in a day?
The ex-date for a demerger is the date on which shares of the parent company start trading without the right to receive shares of the demerged (spun-off) company