When creating a project and trying to add an estimate (my customized form) it shows the default one. I went in and set my template as default and it still isn't showing. I even deleted the project and tried starting fresh.
When entering the estimate, make sure to choose the template by clicking the Customize option at the bottom part of the page.
Also, it seems like you're experiencing a browser-related issue which is why the custom template isn't showing. Let's use an incognito or a private browser to confirm the issue by opening any browser. Please follow these shortcut keys to use an incognito window:
Chrome simply press Ctrl + Shift + N.
Mozilla Firefox and Internet Explorer, press Ctrl + Shift + P.
Safari, press Command + Shift + N. Make sure you're using the latest version.
Check the print and review of the estimate and see if you can see the custom template, then follow the steps toclear your browsing data if it does. This will allow QuickBooks to load as a fresh page to remove any error messages or glitches that may be standing in the way of certain features.