What are the main reasons for Sharia non-compliance even though someone dies leaving Will?

Islamic Will gets challenged in the court because inheritors are unhappy.

All assets have been jointly owned or designated beneficiaries, bypassing the Will and Islamic inheritance.

Islamic Will is created from a typical free Islamic Will template which does not provide a clearer and interpretable snapshot of Islamic inheritance law.

Islamic Will narrates the distribution of assets to one or more specific inheritors rather than following Islamic inheritance law. The result may be that parents, grandparents, children, or grandchildren would deprive of taking an inheritance, which is becoming a norm in most Muslim societies.

Only a few people try to visualize the outcome and effectiveness of the practicality of their Islamic Will. They need to know the implications of Islamic Will regarding marital status, assets ownership, and tax consequences. Only beneficiaries would know how your Islamic Will functions, which will reveal only during probate processing.

Due to the mass migrations of people across the world, Children live in one Country, and other relatives (i.e., Parents, Grandparents, Siblings, etc.) live in another country which creates the challenge for Muslims legally to distribute assets across the border. This issue is increasing daily due to migrations in an upward trend.

Islamic Wills may not be a suitable estate plan in some scenarios, but people assume and create for the sake of it without realizing the consequences. For example, Islamic Will may not be ideal if you have substantial assets or business nationally or internationally.