I missed this news item, but former Bentley employee now-independent CAD journalist Randall Newton covers it at his AEC weblog: Alabama Supreme Court Sends Bentley, Intergraph Countersuits Back for Retrial.
You can read the legal machinations at Mr Newton's weblog, but some background might be in order.
In the 1980s, Intergraph was one of two mighty CAD companies; the other was Computervision. Both companies were turnkey: they sold you the CAD software, they built their own hardware and sold that to you, as well, as a package deal. We're talking $150,000 per license in the days when $150,000 was real money.
Some of the Bentley brothers figured out how to display Intergraph CAD files on lower-cost terminals (a predecessor of today's file viewer software), and then how to edit the files. At first, Intergraph threatened to sue, but then realized that this was a way to get into the low-cost CAD market -- which was threatening Intergraph from the the $1000 VersaCADs and AutoCADs. (Computervision bought out VersaCAD, which is now independent again.)
A deal was struck: Bentley Systems would write the software, while Intergraph would market and sell it. The lawsuit is whether both sides lived up to the terms of the deal. (In the years following, Bentley took on more and more of the responsibilities, and now Intergraph has nothing to do with Microstation at all.)