During the Tesla Model X's much-delayed history, the finger was often pointed towards the innovative, and complex operation of the falcon wing doors as a primary culprit.

And as often as those fingers were pointed towards CEO Elon Musk's much loved new feature, the company would not confirm any one specific issue.

Tesla Model X Falcon Wing Doors - As Forecasted, Not The Easiest Thing To Make

Tesla Model X Falcon Wing Doors - As Forecasted, Not The Easiest Thing To Make

As it turns out...some of those times, it was the doors.

But apparently, it was not Tesla's fault, it was the designer's.

In a lawsuit against a Swiss German supplier contracted to design the door, Tesla details Hoerbiger Automotive Comfort Systems' inability to produce a workable "falcon wing" model in a timely fashion, causing the California automaker to source an alternate supplier who could, causing extended delays in the Model X's launch.

Specific to the lawsuit is a request to stop Hoerbiger from demanding more payments from Tesla after the company was forced to drop the Swiss firm in May of 2015, just 4 months ahead of the Model X's launch.

WSJ explains further

"Tesla claims it paid Hoerbiger, which makes hydraulic lift gates, to develop the vertically rising side doors on its Model X after a competition with several other companies. But between February 2014 and May 2015, the company couldn’t produce a prototype that passed Tesla’s engineering standards.  According to the lawsuit, prototypes from Hoerbiger leaked oil and sagged or produced excessive heat, causing them to stop working."

Tesla Demonstrates Functional Falcon Wing Doors After  Supplier Hoerbiger Had Earlier Failed To Design A Working Model

Tesla Demonstrates Functional Falcon Wing Doors After  Supplier Hoerbiger Had Earlier Failed To Design A Working Model

A Tesla also spokeswoman offered this comment to the Wall Street Journal:

“We were forced to file this lawsuit after Hoerbiger decided to ignore their contracts with us and instead demanded a large sum of money to which they are not entitled.We will vigorously prosecute this case.”

Hoerbiger is seeking payment for the work not completed, but that it was promised.  Tesla to date has paid $3 million in prototyping parts and engineering.  After dismissing Hoerbiger last May, Tesla built an alternate electromechnical door system hired a new supplier.

“Tesla incurred millions of dollars in damages, including, but not limited to costs of re-tooling the entire vehicle in order to support a different engineering solution.... In addition, Tesla had to pay the new supplier a premium to rush out a workable solution."

The Wall Street Journal