Example on test2.wikipedia.org. Steps to reproduce:

1. Create a new empty page on your MediaWiki installation
2. Paste one of the following as raw source Wiki code for the page:

== Section 1 ==
{| border="1"
 |Table from section 1
 |-}
== Section 2 ==

or (for more obvious problem):

== Section 1 ==
Start of section 1.
{| border="1"
 |Table from section 1
 |-}
End of section 1.

== Section 2 ==
Start of section 2.
{| border="1"
 |Table from section 2
 |-}
End of section 2.

3. Save the page
4. Look at the result, table is misplaced and out-of-order with text and sections:

5. Replace terminating |-} in the end of tables with correct |}.
6. Now tables are in correct order with the text and are in correct sections.