Hi,

The issue is in the line,

spObj =self.env['social.approval'].search([('booking_id', '=', rec.id)])

From the above code you are getting multiple records to the variable spObj, so you have to iterate the spObj over a for loop or give limit=1, along with search.

spObj =self.env['social.approval'].search([('booking_id', '=', rec.id)], limit=​1)

or

spObj =self.env['social.approval'].search([('booking_id', '=', rec.id)], limit=​1)

for obj in spObj:

for obj.special_approval_line_ids

Like this update the code and see.

Thanks