There are two WTO disputes involving the United States (one offensive, one defensive) where the parties have been requesting the postponement of the public circulation or the issuance of the panel report for quite a while now. For one of them the final report has definitely been issued to the parties; for the other, the interim report may have been issued to the parties, but I'm not sure.
The first is U.S. - Fish Fillets from Viet Nam (DS536). In June 2020, the Panel announced that the final report had been issued to the parties, but the parties had requested a delay in public circulation of the report because they were trying to negotiate a solution:
... The Panel issued its final report to the parties on 7 February 2020. Public circulation of the report was originally scheduled for 17 March 2020.
However, due to the COVID pandemic the report has not yet been circulated, as to date the Secretariat has not been in a position to produce and distribute paper copies of the report per the requirements of the decision in WT/DSB/6. Nor have delegations had access to the premises to collect any such physical copies.
On 2 June 2020 the United States and Viet Nam jointly informed the Panel that they were engaged in discussions with respect to the resolution of this dispute. In that context, they requested that the Panel postpone the circulation of the final report for three months, until 31 August 2020.
The circulation of the final report has therefore been postponed until 31 August 2020.
On September 2, 2020, the panel announced that:
On 28 August 2020 the United States and Viet Nam jointly informed the Panel that they remained engaged in discussions with respect to the resolution of this dispute. In that context, they requested that the Panel further postpone the circulation of the final report until 12 October 2020.
The circulation of the final report has therefore been postponed until 12 October 2020.
And then it just kept making similar communications: here, here, here, here, here, here and here. The latest communication, from February 16, 2022, says: "The circulation of the final report has therefore been postponed until 18 May 2022. "
The second dispute is the Article 21.5 proceeding in India - Agricultural Products (DS430). In that case, the panel announced a delay on May 22, 2018 as follows:
On 23 November 2017, the Panel informed the DSB that, due to the complexity of the issues in dispute, it expected to issue its final report to the parties by the end of May 2018.
The Panel now wishes to inform the DSB that the parties have jointly requested the Panel to delay the issuance of its Report. The Panel has accepted the parties' request, and accordingly now expects to issue its Final Report in September 2018.
Based on the dates provided, with a May 22 announcement that the panel expected to issue its final report by the end of May, it seems likely that an interim report had already been issued, although the panel did not say anything about that. Subsequently, the panel made similar communications: here, here, here, here, here, here, here, here, here, here, here, here and here. The latest communication, from January 7, 2022, says: "The Panel has accepted this request, and accordingly wishes to inform the DSB that it now expects to issue its Final Report by the end of May 2022."
For both disputes, the delays and negotiations have lasted quite a long time. I haven't checked to see if these disputes have set a record for most delay announcements, but they must be near the top of the list anyway.
There's nothing wrong with engaging in these negotiations after a report is issued, but it seems a bit odd that the negotiations keep dragging on like this and the WTO disputes continue on in this way. It is not clear what the negotiations involve and when there will be a resolution. It kind of seems like there is a new U.S. strategy to negotiate rather than litigate trade disputes, and maybe this is part of it. Given that both India and Viet Nam are in the "Indo Pacific" region, I wonder if these disputes are being folded into the broader Indo Pacific Economic Framework, and that a resolution will be part of some kind of negotiating package in that context. That's just speculation though.