I think @sevensevens' are great suggestions, I would like to add that you need to change your process slightly. Your problem is that apparently the nature of the work of your team needs some kind of revision, but for some reason that is not part of the work that has to be done, so there is a false sense that it is done before being reviewed.
Basically, you need to change your definition of done. I would probably discuss it with the team as everyone had suggested and see how to better fit this revisions as part of the workflow.
This makes the revisions part of the work they have to do and not something "optional".
For example if you are writing documents, or creating whatever kind of element that could benefit from someone else's reviews, you could add a step to the end of the process where someone else has to "review it", be it, read the document, or if it some kind of presentation see it. Then has to input their opinion, things to correct, things they liked, whatever you and your team dim appropiate, and then you leave another day after that too implement those "changes".
In order for this to work, these reviews need to have some kind of paper trail, like if you had the tracking software suggested would be great, but with a simple email, copying you, listing the findings would be alright too. This will force a natural "earlier" deadline because now the work has to be reviewed by someone else. And cause peer pressure, because people won't want to mess with their coworkers' deadlines either.
However if this is some kind of creative effort, it feels odd that you would wait till the end to make these reviews. It also feels odd that they are not part of the process. It would be better to integrate several checkpoints to the process to review key things. Like close to the begining you could check what approach is going to be taken, later on how it is going and what is needed. Daily meetings, like someone else suggested, are great to help people with every day issues for example.
An important thing with these changes to the workflow though, is not to make it endless, there has to be a point where it ends. Set specific checkpoints and actions to be taken and go through with it. Even if not every tiny issue is addressed, you will be better off than right now where you have no time to fix even major issues.
Also later on if there were things in the document or whatever is that your team is producing that were not addressed, you can hold a meeting with the 2 people involved and discuss why no one noticed those issues.
Finally, is it worth it? I mean, it seems this has been happening for a while, maybe it is not so important that those reviews are not implemented? If it is important, discuss it with your team and tell them the immediate and long term consequences of what happened. For example the team has a poor image in the organization because they always deliver late or unpolished work; wich could have a bad impact in their careers and opportunities for advancement.