The FAR was changed in 2018 to revise the GAO protest jurisdiction regarding orders under IDQ contracts:
16.505 -- Ordering.
(i) No protest under subpart 33.1 is authorized in connection with the issuance or proposed issuance of an order under a task-order contract or delivery-order contract, except for—
(A) A protest on the grounds that the order increases the scope, period, or maximum value of the contract; or
(1) For agencies other than DoD, NASA, and the Coast Guard, a protest of an order valued in excess of $10 million (41 U.S.C. 4106(f)); or
(2) For DoD, NASA, or the Coast Guard, a protest of an order valued in excess of $25 million (10 U.S.C. 2304c(e)).
(ii) Protests of orders in excess of the thresholds stated in 16.505(a)(10(i)(B) may only be filed with the Government Accountability Office, in accordance with the procedures at 33.104.
See also https://www.mcguirewoods.com/client-resources/Alerts/2018/5/New-GAO-Protest-Rules-Take-Effect-May-31