If you publish a job with a bids due date new bidding and updating bids becomes deactivated from the expiration of that day (up to 11.59pm in your timezone).
Prior to this time a user is free to accept any bid that has been made. And after this time has expired the user will be reminded that they may wish to accept a bid.
Whether the user changes the bids due date and/or wishes to accept a bid prior to the bids due date expiring is in the discretion of the user who should follow any internal policies of their organisation regarding tendering. Bidders are advised that this is the case and that no specific rule is enforced by the platform.