The reason for West Brom's points deduction has now been revealed.
They breached PSR due to 2 errors:
1. The club took out a loan under the previous owner and then forgot to add in the loan interest amount into their accounts numbers submitted to the EFL
2. They excluded some spending due to classing it under the heading of Community Development Expenditure, which is allowed and doesn't impact any PSR calculations, but their spending under this heading was 'in-kind donations of the Club’s facilities, staff time and resources to its official charity partner, The Albion Foundation', which is not what the EFL say Community Development Expenditure is, so those numbers then had to be added into the total PSR calculation
Their final PSR calculation then had them breaching by £1.97M