I don't think what you describe is an error as such, just normal theme behavior, but your question is not clear.
Are you just asking how to display excerpts on the home page rather than full posts?
If so there are three methods...
1) Best for SEO
Create a custom (nicely keyworded) excerpt in the post editor (scroll down the post editor screen to find it).
If you cant find the excerpt box click on the 'Screen options' tab at the top right of the post editor to reveal it.
2) Easy and precise
Use the <!--more--> tag in your posts to define where the post 'cuts off' on the home page. There is a button the post visual editor and html editor to add this tag.
3) Change the code... (heatmap Adaptive is hook based so its easy to do)
In index.php find...
This will give you automatic WordPress excerpts on the home page.