There are many reasons that might lead the stakeholder to intentionally or unintentionally hide information during the project. Throughout my project management career, I've faced 2 common scenarios during which the stakeholder was either hiding information or sharing wrong information on purpose, and one scenario where the stakeholder was unintentionally hiding information.
Starting with the intentional information hiding, the first scenario is when the stakeholder is reluctant to change and hopes that by hiding information or by even sharing wrong information the project would simply fail which allows him/her to stay in their comfort zone. The second scenario is when the stakeholder don’t really trust the Project Manager and his team and feels that by sharing information he would actually be exposing critical company related information that might in a way or another get to the hands of competitors. In some cases, the above mentioned scenarios are combined which piles up additional challenges to the project.
As for unintentional information hiding, sometimes the stakeholder is always busy and unresponsive and their attention is focused elsewhere and the Project Manager can’t really force him/her to provide the needed input. This is way trickier to solve and it sometimes requires the project Manager to take some bold decisions.