Plaintiff SURFCAST INC represented by AMY ARAYA DLA PIPER LLP (US) BENJAMIN S. PIPER PRETI, FLAHERTY LLP ONE CITY CENTER GIANNI MINUTOLI DLA PIPER LLP (US) NEAL F. PRATT EATON PEABODY ONE PORTLAND SQUARE TIMOTHY J. BRYANT PRETI, FLAHERTY, BELIVEAU, & PACHIOS, LLP ONE CITY CENTER AMY H. WALTERS DLA PIPER LLP (US) ERICA JUDITH PASCAL DLA PIPER LLP (US) JAMES M. HEINTZ DLA PIPER LLP (US) JOHN ALLCOCK DLA PIPER LLP (US) KATHRYN RILEY GRASSO DLA PIPER LLP (US)TIFFANY CAROL MILLER DLA PIPER LLP (US) ATTORNEY TO BE NOTICED
Defendant MICROSOFT CORPORATION represented by PETER J. BRANN BRANN & ISAACSON RISHI PREET CHHATWAL SIDLEY AUSTIN LLP DAN K. WEBB WINSTON & STRAWN, LLP ELLEN S. ROBBINS SIDLEY AUSTIN LLP ONE SOUTH DEARBORN STREET HERMAN FITZGERALD WEBLEY, JR. SIDLEY AUSTIN LLP ONE SOUTH DEARBORN STREET JOHN WEATHERBY MCBRIDE SIDLEY AUSTIN LLP ONE SOUTH DEARBORN STREETJOSEPH A. MICALLEF SIDLEY AUSTIN LLPRICHARD ALAN CEDEROTH SIDLEY AUSTIN LLPSTACY O. STITHAM BRANN & ISAACSONWONJOO SUH SIDLEY AUSTIN LLP ATTORNEY TO BE NOTICED
Counter Claimant MICROSOFT CORPORATION represented by PETER J. BRANN (See above for address) RISHI PREET CHHATWAL DAN K. WEBBELLEN S. ROBBINS HERMAN FITZGERALD WEBLEY, JR. JOHN WEATHERBY MCBRIDE JOSEPH A. MICALLEF RICHARD ALAN CEDEROTH STACY O. STITHAMWONJOO SUH (See above for address) ATTORNEY TO BE NOTICED
Counter Defendant SURFCAST INC represented by AMY ARAYA (See above for address) BENJAMIN S. PIPER GIANNI MINUTOLI NEAL F. PRATT TIMOTHY J. BRYANT AMY H. WALTERS ERICA JUDITH PASCAL JAMES M. HEINTZ JOHN ALLCOCK KATHRYN RILEY GRASSO TIFFANY CAROL MILLER (See above for address) ATTORNEY TO BE NOTICED
AMENDED ORDER VACATING THE MAGISTRATE JUDGE’S DISQUALIFICATION OF DR. MARK ACKERMAN AS AN EXPERT WITNESS FOR MICROSOFT CORPORATION 
JOHN A. WOODCOCK, JR. CHIEF UNITED STATES DISTRICT JUDGE
In this patent infringement suit over U.S. Patent No. 6,724,403 (issued Apr. 20, 2004), SurfCast, Inc. (SurfCast) sought to preclude Microsoft Corporation (Microsoft) from using Dr. Mark Ackerman as a retained expert witness. The Magistrate Judge disqualified Dr. Ackerman on the ground that SurfCast established a confidential relationship with him in a single twenty-three minute telephone call one year before Microsoft retained him as an expert witness. Before the Court is Microsoft’s objection to the Magistrate Judge’s disqualification order. The Court, concluding that the legal standard for disqualification applied by the Magistrate Judge was too lenient to SurfCast, vacates the disqualification and remands for the Magistrate Judge to determine in the first instance whether SurfCast established a relationship with Dr. Ackerman sufficiently substantial to make disqualification an appropriate remedy.
I. LEGAL STANDARD
When the Magistrate Judge issues an order on a non-dispositive matter, the Court reviews factual findings for clear error and legal findings de novo. See PowerShare, Inc. v. Syntel, Inc., 597 F.3d 10, 15 (1st Cir. 2010); Charles Alan Wright, Arthur R. Miller & Richard L. Marcus, 12 Federal Practice and Procedure § 3069, at 350-56 (2d ed. 1997 & Supp. 2013).
Because legal issues will often be entwined with factual issues that are in turn tinged with aspects of discretion, there should customarily be little question that a district judge retains authority to modify an unwarranted action by a magistrate judge even after assigning a matter to the magistrate judge for decision.
Wright, Miller & Marcus, supra, at 355. “The decision to disqualify an expert is discretionary.” Thompson, I.G., L.L.C. v. Edgetech I.G., Inc., 11-12839, 2012 WL 3870563, at *2 (E.D. Mich. Sept. 6, 2012).
A. Procedural Posture
On August 27, 2013, the Magistrate Judge presided over a hearing on certain discovery disputes between SurfCast and Microsoft. Report of Hr’g and Order re: Disc. Disputes (ECF No. 111). At that hearing, SurfCast objected to Microsoft’s use of Dr. Ackerman as an expert witness. Id. at 2. The Magistrate Judge, over Microsoft’s objection, ordered SurfCast to produce sworn statements from Attorney Pascal and Dr. Ackerman, as well as certain notes that the SurfCast attorneys took during their 2012 conversation with Dr. Ackerman. Id. The Magistrate Judge considered these documents in camera and ordered both parties to submit letter briefs on the disqualification issue. Id. The Magistrate Judge issued a memorandum decision on September 30, 2013, disqualifying Dr. Ackerman as an expert witness for Microsoft. Memorandum Decision on Mot. to Disqualify Expert Witness (ECF No. 121) (Mem. Dec.).
Microsoft filed an objection to the Magistrate Judge’s decision on October 10, 2013. Def. Microsoft’s Objection to Mem. Dec. (ECF No. 128) (Def.’s Objection). With this objection, Microsoft submitted an affidavit by Dr. Ackerman describing his version of his communication with SurfCast. Def.’s Objection Attach. 1 Decl. of Dr. Mark S. Ackerman (ECF No. 128) (Ackerman Decl.). SurfCast replied to Microsoft’s opposition on October 28, 2013. Pl. Surfcast’s Resp. to Def.’s Objection to Mem. Dec. (ECF No. 134) (Pl.’s Reply). On October 30, 2013, Microsoft moved for leave to file a reply in support of its objection. Def. Microsoft’s Mot. for Leave to File a Reply (ECF No. 136) (Def.’s Mot for Leave to File Reply). SurfCast responded in opposition to this motion on October 31, 2013. Pl.’s Objection to Def.’s Mot for Leave to File Reply (ECF No. 137). The Court granted Microsoft’s motion, Order Granting Mot. for Leave to File Reply (ECF No. 147), and Microsoft filed its reply on November 27, 2013. Def.’s Reply in Support of Its Objection to Mem. Dec. to Disqualify Expert Witness (ECF No. 148) (Def.’s Reply). SurfCast filed a sur-reply on December 11, 2013. Pl.’s Sur-Reply to Def.’s Objection to Mem. Dec. to Disqualify Expert Witness (ECF No. 149) (Pl.’s Sur-Reply).
B. Historical Facts
The Court adopts the Magistrate Judge’s recital of the facts of this matter. Dr. Ackerman had only one substantive conversation with counsel for SurfCast, Erica Pascal, Esq., and Tiffany Miller, Esq. Mem. Dec. at 1. That conversation took place on August 29, 2012, and lasted twenty-three minutes. Id. Before that telephone conversation, on August 23 or 24, 2012, Attorney Pascal sent Dr. Ackerman via email a confidentiality agreement that she asked him to sign before they could engage in ...