A July 6 order resolving a bitter disqualification fight between Netflix Inc. and its lawyers at Winston & Strawn LLP is the latest example of the acrimony that “advance conflict waivers” can engender between corporations and the law firms they hire.

The order disqualifying Winston—issued by a federal bankruptcy judge presiding over a high-stakes licensing dispute between Netflix and a financially troubled film studio—could emerge as a blueprint for a particularly contentious category of disqualification motions: those alleging law firms...