An Inter Creditor Agreement (ICA) is a legal agreement between two or more creditors who have lent money to the same borrower. The agreement states each creditor's rights and responsibilities regarding their loans and establishes a framework for cooperation and coordination among them (PDF).
Exchanges (PDF) mandate brokers to display a notification stating that the company's lenders have signed an ICA every time you place an order for the company's stock.
After you click on Buy for such stocks, another nudge will appear. Click on Proceed to purchase the stock. This requirement aims to ensure that you make informed decisions before buying a specific stock.