In the frenzied week after Lehman Brothers filed for bankruptcy on 15 September last year, lawyers for Lehman (a group that included bankruptcy counsel at Weil Gotshal & Manges, Lehman's longtime outside counsel at Simpson Thacher & Bartlett and a team from Sullivan & Cromwell) worked around the clock with lawyers representing Barclays to arrange the sale of Lehman's prized US assets.

On 22 September, Lehman and Barclays (represented by Cleary Gottlieb Steen & Hamilton and Clifford Chance) struck a deal under which Barclays acquired Lehman's US capital markets unit, billions in liabilities, and some of Lehman's real estate in return for about $1.5bn (£961m).

Now Lehman is investigating whether Barclays got a better deal than it should have, according to the New York Times. In court papers filed on Monday (18 May), a new team of Lehman lawyers (this time from Jones Day) argue that Barclays was able to buy Lehman's best US assets for so little – about $250m (£160m) when real estate is taken out – because it agreed to assume various liabilities, including about $2bn (£1.3bn) in bonuses owed to Lehman employees who would likely transfer to Barclays.

But now it appears "that these assumed liabilities were significantly overstated or inaccurate, and, further, that Barclays may not have actually paid these obligations," the filing says. In fact, the amount owed to those employees might have been 'only' $600m-$700m (£384m-£448m) – far less than dealmakers estimated at the time.

As part of the investigation, Lehman is asking Barclays to turn over a host of documents related to the bonus payments and other liabilities. Barclays has not co-operated with those requests, the filing says.

Barclays has hired Jonathan Schiller of Boies Schiller & Flexner as counsel in the matter. Schiller immediately went to work, writing to a Jones Day team that includes partners Robert Gaffey, William Hine, and Jayant Tambe, and not-so-gently informing the team that their own application to represent Lehman listed as a client the Barclays unit at the centre of the Lehman purchase. The Jones Day team was conflicted out, Schiller wrote, and in acting otherwise they were "disregarding the disqualification of their own firm."

Jones Day replied that they had accidentally listed the Barclays unit in question on their application, and have since amended the documents, court records show.

This is not the first possible glitch in the Lehman-Barclays deal. As first reported on Above the Law in October, a Cleary associate accidentally screwed up an Excel spreadsheet that listed contracts that were to change hands in the deal. The error resulted in Barclays assuming nearly 200 contracts it did not want. That has since been corrected.

So did the deal lawyers miss something else, or overvalue the Lehman liabilities? Only time will tell. It should be noted that Barclays has resisted Lehman's discovery requests so far because the court-appointed examiner in the case, Anton Valukas of Jenner & Block, is also looking into the deal as part of his broader investigation of Lehman's collapse.

And according to a filing from Friday (15 May), Valukas is giving a few lucky out-of-work lawyers some work in the case. Specifically, he has asked the court for permission to hire 17 contract lawyers for document review at a cost of $43.50 (£28) per hour.

So the Lehman Brothers bankruptcy – big enough to give work to lawyers across the Am Law spectrum.

This article first appeared on The American Lawyer, Legal Week's US sister title.