After further checking into this problem, I discovered that you're right. I did change something that allowed the featured products page to be displayed on all pages.
Here's what I did to accidentally create the problem and then solve it, in hopes that my plunder will help someone else:
Last week, I edited customer/home.tpl, so that the placement of my featured products was displayed more near the center of the home.php page. To accomplish this, I simply moved the following line of code:
{include file="customer/main/featured.tpl" f_products=$f_products} further up. However, the new location of this code effectively placed it outside of the conditional statement: {if $main eq "catalog" and $current_category.category eq ""}
which caused my problem of having the featured products being displayed on all pages.
To solve the problem, I simply surrounded the featured products code with the conditional.
{if $main eq "catalog" and $current_category.category eq ""}
{include file="customer/main/featured.tpl" f_products=$f_products}
{/if}
Doing this seems to have corrected the problem. Thanks for pointing this blind man in the right direction.