I can help you isolate unexpected behaviors within QuickBooks Online, crossroadsbiryan.
There are times that the browser is full of frequently-accessed page resources, thus causing websites, like QuickBooks Online (QBO), to have unusual responses. You can try logging into your QBO account using a private browser. To use a private browser, here's how:
Google Chrome: Ctrl + Shift + N
Mozilla Firefox: Ctrl + Shift + P
Safari: Command + Option + P
Then, create and save the Bill again. If this works, it means that you need to clear your browser's cache so the system can start fresh. If you get the same result while using a private browser, I recommend switching to a different browser.
Here are a few resources that can help you manage your vendor transactions: