Thanks for joining this thread, rmmack.
 

Since you've performed IamjuViel's troubleshooting steps, but your estimates continue showing open balances after being converted to invoices, I'd recommend getting in touch with our Customer Care team. They'll be able to pull up your account in a secure environment, conduct further research, and create an investigation ticket if necessary.
 

They can be reached while using QuickBooks.
 

Here's how:

1. In the top menu bar, go to Help, then QuickBooks Desktop Help.
2. Click Contact Us.
   
3. Enter a brief description of the issue in our Ask a question (or tell us what's wrong) field and hit Continue.
   
4. Select We’ll contact you for a callback or Message Us to start an instant messaging session.

Be sure to review their support hours so you'll know when agents are available.
 

As for your feature request, I can certainly understand how an automated ability for making estimates inactive after a certain period of time could come in handy and have submitted a suggestion about it as of today. For the time being, you'll have to use your Mark As Inactive option on your estimate transaction screen. Selecting this will manually mark a record as inactive.

You can also submit your own suggestions while using QuickBooks.
 

Here's how:

1. In your top menu bar, go to Help, Send Feedback Online, then Product Suggestion....
2. Choose a Type of Feedback and Product Area (optional) from the available drop-down menus.
3. Enter any suggestions/feedback in your Here is my suggestion: field.
4. If you'd like, include your name/email in the My name is: (optional) and My e-mail address is: (optional) fields.
   
5. Select Send Feedback.
   

Your feedback's definitely valuable to Intuit. It will be reviewed by our Product Development team and considered in future updates. You can stay up-to-date with the latest news about your product by reviewing our QuickBooks Blog.
 

I'll be here to help if there's any questions. Have a wonderful day!