You can prepare an incident report with all the details of the issue and then ask the leadership for an enquiry. Once the issue is identified, then you might want to sensitize all the employees in that particular project of the issue and its impact on the project and the organization as a whole.
After conducting the interview, analyze the results through which the root cause can be identified, if it is a person, then you can call that person separately and give him a chargesheet for an explanation. If it is satisfactory, then you can close the issue by issuing a memo to that person and request him not to repeat the same. In case the explanation is not satisfactory, then please proceed as per the instructions of the leadership.
Remember, the whole process of enquiry should be conducted by an HR person and another person in a responsible position who are not involved in the project to avoid any bias.
Please document this entire process and file it in case you require it further reference.