Even as Wells Fargo was reeling from a major scandal in its consumer bank last year, officials in the company’s mortgage business were putting through unauthorized changes to home loans held by customers in bankruptcy, a new class action and other lawsuits contend.

The changes, which surprised the customers, typically lowered their monthly loan payments, which would seem to benefit borrowers, particularly those in bankruptcy.

But deep in the details was this fact: Wells Fargo’s changes would extend the terms of borrowers’ loans by decades, meaning they would have monthly payments for far longer and would ultimately owe the bank much more in interest.

Any change to a payment plan for a person in bankruptcy is subject to approval by the court and the other parties involved.

But Wells Fargo put through big changes to the home loans without such approval, according to the lawsuits.

The changes are part of a trial loan modification process from Wells Fargo. But they put borrowers in bankruptcy at risk of defaulting on the commitments they have made to the courts, and could make them vulnerable to foreclosure in the future.

A spokesman for Wells Fargo, Tom Goyda, said the bank strongly denied the claims made in the lawsuits and particularly disputed how the complaints characterized the bank’s actions.

Wells Fargo contends that the borrowers agreed to the changes and the bankruptcy courts were notified.

“Modifications help customers stay in their homes when they encounter financial challenges,” Goyda said, “and we have used them to help more than 1 million families since the beginning of 2009.”

According to court documents, Wells Fargo has been putting through unrequested changes to borrowers’ loans since 2015.

During this period, the bank was under attack for its practice of opening unwanted bank and credit card accounts for customers to meet sales quotas.

It is unclear how many unsolicited loan changes Wells Fargo has put through nationwide.

The lawsuits contend that Wells Fargo puts through changes on borrowers’ loans using a routine form that typically records new real estate taxes or homeowners’ insurance costs that are folded into monthly mortgage payments.

Upon receiving these forms, bankruptcy court workers usually put the changes into effect without questioning them.

It is unclear why the bank would put through such changes.

On one hand, Wells Fargo stood to profit from the new loan terms it set forth, and, under programs designed to encourage loan modifications for troubled borrowers, the bank receives as much as $1,600 from government programs for every such loan it adjusts, the class-action lawsuit said. But submitting the changes without approval violates bankruptcy rules and puts the bank at risk of court sanctions and federal scrutiny. When a lawyer for a borrower has questioned the changes, Wells Fargo has reversed them.

This is not the first time Wells Fargo has been accused of wrongdoing related to payment change notices on mortgages that it filed with the bankruptcy courts.

Under a settlement with the Justice Department in November 2015, the bank agreed to pay $81.6 million to borrowers in bankruptcy whom it had failed to notify on time when their monthly payments shifted to reflect different real estate taxes or insurance costs.

That settlement — in which the bank also agreed to change its internal procedures to prevent future violations — affected 68,000 homeowners.

In the class-action lawsuit filed last week, the lead plaintiffs are a couple in North Carolina who say that Wells Fargo submitted three changes to their payment plan in 2016 without approval.

The first time, Wells Fargo put through the changes without alerting them, the couple, Christopher Dee Cotton and Allison Hedrick Cotton, say.

The Cottons’ monthly payments declined with every change, dropping to $1,251 from $1,404.

In the documents Wells Fargo filed — but did not get approved by the borrowers, their lawyers or the court — was the news that the bank would extend the Cottons’ loan to 40 years, increasing the amount of interest they would have to pay. Before the changes, the Cottons owed roughly $145,000 on their mortgage and were on schedule to pay off the loan in 14 years. Over that period, their interest would total $55,593.

Under the new loan terms, the Cottons would have incurred $85,000 in interest costs over the extended period, on top of the $55,593 they would have paid under the existing loan, their court filing shows.

Theodore O. Bartholow III, a lawyer for the Cottons, said Wells Fargo’s actions contravened the intent of the bankruptcy system.

“When it goes the right way, the debtor and mortgage company agree to do a modification, go to court and say, ‘Hey judge, modify or change the disbursement on my mortgage.’”

Goyda, the Wells Fargo spokesman, denied that the bank had not notified borrowers.

“The terms of these modification offers were clearly outlined in letters sent to the customers and/or to their attorneys, and as part of the Payment Change Notices sent to the bankruptcy courts,” he wrote by email.

Goyda said that “such notices are not part of the loan modification package, or part of the documentation required for the customer to accept or decline modification offers.”

He added, “We do not finalize a modification without receiving signed documents from the customer and, where required, approval from the bankruptcy court.”