I opened it in Word 2010 and it does not look that unusual to me. The section break when inserted at the end of a line extends to the right edge of the page in the display (actually off the page).
00 deleteme 1.png

It does not cause any problems except that sometimes I have trouble finding the things in print view. You can't see what kind of section break it is without inserting a line/paragraph break before it or switching into draft view.

That said, a more important issue is that you should not be using a section break there at all. Your letterhead should be in the first-page header of your template.

• Setting Up Letter Templates - Ribbon versions - by Suzanne Barnhill
• How can I get a different header/footer on the second page?

I really like the power that sections add to a complex document. However, unnecessary section breaks can really complicate editing.

• Sections / Headers and Footers in Microsoft Word (Ribbon Versions)
• Header/Footer Settings Recap