A planned data transfer conducted ahead of the Defense Health Agency’s transition to new Tricare contracts resulted in 16,000 beneficiaries being dropped from the Pentagon’s personnel system, causing a temporary loss of health care benefits.

Officials announced Friday on the Tricare website and in emails to affected personnel and retirees that they were “inadvertently dropped” from the Defense Enrollment Eligibility Reporting System, or DEERS, during a planned transfer of beneficiary enrollment information.

According to the Defense Health Agency, an incomplete file contributed to the loss of data during a scheduled monthly upload, affecting 16,000 retirees and family members from the Coast Guard, National Oceanic and Atmospheric Administration, or Public Health Service.

Read Next: Live Election Updates

The Coast Guard sent an alert Saturday saying personnel officials were working with the Defense Manpower Data Center to resolve the issues, estimating that it would take 48 to 72 hours to fix.

They emphasized that the problem would not affect benefits eligibility or coverage and that patients would be reimbursed for any expenses incurred during the outage.

“We regret the inconvenience and uncertainty this outage has caused,” Coast Guard officials wrote in an email to members and retirees. “We appreciate your patience as our teams work to resolve this situation as fast as possible.”

The Defense Manpower Data Center and DEERS Support Office announced they had restored eligibility for most beneficiaries by Sunday.

“The outage was brief, lasting only 48 hours,” DHA spokeswoman Karen Roberts said.

The Defense Health Agency undertook a multi-day enrollment freeze from Oct. 25 to Oct. 28 to upgrade software, perform maintenance and begin the transfer of beneficiary enrollment information to TriWest Healthcare Alliance, the contractor that will assume responsibility for the Tricare West Region beginning Jan. 1.

In 2017, the last time Tricare consolidated its regions and changed contractors, the enrollment freeze took more than three weeks and resulted in thousands of beneficiaries being dropped.

A DHA official told Military.com that they hoped to prevent some of the issues seen in 2017 by starting the data transfer in October rather than December and ensuring that any DEERS transactions attempted during the blackout period would be held in a “pending” status for later updates in the DEERS database.

“There should be no noticeable delays in referrals, authorizations or other transactions,” DHA spokeswoman Brenda Campbell said in a statement Oct. 22.

In her statement, Roberts reiterated that the issue was not tied to “contract transition activities.”

“This was due to a data transfer between the Coast Guard and DMDC [Defense Manpower Data Center],” Roberts said.

On Monday, Coast Guard officials said the DMDC had restored “99% of our retired community’s Tricare eligibility” and would work this week to address the remaining cases.

They advised all members to check their DEERS status and eligibility by going to the milConnect website. Those who need emergency medical assistance or urgent care while they aren’t listed as eligible in the system should go get care, keep all receipts and records, and contact their Tricare regional contractor for reimbursement, they added.

“Due to the brief nature of the outage, and because it was over the weekend, it’s unlikely there will be billing disputes. Any issues should be addressed by beneficiaries contacting their Tricare contractor,” Roberts said.

Tricare’s new regional contracts will begin Jan. 1. Starting New Year’s Day, Humana Military will continue managing the Tricare East Region, but TriWest Healthcare Alliance will take over the West Region and add Arkansas, Illinois, Louisiana, Oklahoma, Texas and Wisconsin to its area of responsibility.

Through Dec. 31, if Tricare beneficiaries want to change their primary care manager if they are in Tricare Prime or switch their Tricare plan as the result of a qualifying life event, they should call Humana Military at 800-444-5445 if they live in the East Region or Health Net Federal Services at 844-866-9378 if they live in the current West Region.

If they wish to switch plans between Tricare Prime and Tricare Select during Open Season, which runs from Nov. 11 to Dec. 10, they should call Humana in the East Region and TriWest Healthcare Alliance after Nov. 11 in the West Region.

Related: Tricare Enrollment Freeze Coming, But Officials Say Contract Transfer Will Avoid Headaches of 2017 Change

Story Continues