Having had a look at this on a test system, and changing the Personal settings to 'show window maximised', I saw the same behaviour as you, so I'll be passing this down to Dev. The Problem ID (at least for the moment) seems to be 1571 - SD to 'remember' when windows are resized - but I'll keep you updated.
Just to give you some more info on this. When a collection window is displayed there are two things that will happen depending on the type of collection you are viewing. I suspect that you actually only get this problem when you are looking at Assignmnet, Reminders and Task collection windows. If you are looking at a Note window, it sizes correctly. The difference is because the collections I have mentioned have internal processes linked to them. These run in the same way the as the processes that you can edit, but are hidden. For any window on a process, it takes the default size of the Console window when being displayed as a window rather than maximised. To test this, open Console and set to a window and compare the sizes. Now there is a way to get Console to set and remember this size.
1. Resize the window to an acceptable size that will show all of the collection data.
2. Close down console using File Exit.
3. Restart Console and then maximise.
This should now be the size when you open the collection.
Having said all of that, those collections should resize in the same way that the non-process collections do, so I am in agreement with Jean that this is logged and passed on to development to investigate further.