I have few clients who received NOA for 2024 tax and received significantly less refund or more amount to pay that what we calculated suing Profile. 

There are no details avilable in NOA except "Because of a calculation error, we changed your federal tax payable to $....... As a result, your total payable has changed."

Double checked all the entries in tax return but everything seems perfect. Profile Helpdesk also confirmed this  and said they do not see any error in software. 

Tried calling CRA since past several days [atleast 50 times] but no luck so far, hence thought of find out from Community if any one knows the reason for this.