Short answer: They are not out of order/it is not supported in Blender.
Long answer: they are sorted, just not in the way you would expect.
They are sorted in purely alphabetical order, from a cold computer perspective
Object11 alphabetically speaking comes before
What you are expecting is Natural Sort Order, which is not widely supported in software, and must be explicitly coded to do so, which is apparently not the case in Blender Outliner.
That is why using leading zeros in your digital names (files, objects, data values, etc.) like
Object.001 is always a good idea.
How to work around it :
Make sure in the outliner View Menu > Sort Alphabetically is ticked.
If you really want them to be sorted use a third party addon like Name Panel to manually rename the objects and add leading zeros.