Carpentry disputes generally arise out of poor contractual documentation and/or defective work and/or materials.
Plans often lack detail and specifications are often general and not project specific. Quotations will often omit (deliberately or accidentally) items of work but not expressly state so or may be presented in the form of estimates for items of work to be undertaken that are inaccurate for the work/materials that are in fact required to be undertaken. Many owners and contractors will request changes/variations to the scope of work and specification as work progresses and no price will be agreed in advance.
On the other hand, mistakes and errors are a feature of any carpentry related work and some carpentry contractors fail to have adequate quality assurance processes in place to ensure they achieve the agreed/specified scope of work to the specified standard, and/or to complete their work by the due date for completion.