Facebook’s ad systems have reportedly been struggling to manage the vast amount of user data they collect, according to a leaked report from the company’s privacy engineers. The report, written last year and published by Vice on Tuesday, warns that Facebook could face difficulties with regulators in the US, Europe, India, and other countries.

The root of the issue lies in the “open borders” of the system that Facebook’s parent company, Meta, has built. As the engineers explain in the report, “Imagine you hold a bottle of ink in your hand. This bottle of ink is a mixture of all kinds of user data … You pour that ink into a lake of water (our open data systems; our open culture) … and it flows … everywhere. How do you put that ink back in the bottle? How do you organize it again, such that it only flows to the allowed places in the lake?”

This system makes it difficult for Facebook to assure external groups that the data is not being used for purposes beyond what regulations such as the EU’s General Data Protection Regulation (GDPR) allow. In a statement to CNET, Meta claimed that the leaked document does not accurately reflect the company’s “extensive processes and controls” to comply with regulations and that the data lake analogy lacks context. A company spokesperson further commented that “new privacy regulations across the globe introduce different requirements and this document reflects the technical solutions we’re building to scale the current measures we have in place to manage data and meet our obligations.”