Just to clarify, what specific transaction are you trying to create? This is for me to further check on it and provide the necessary steps to resolve it.
In the meantime, let's login to your QuickBooks Online account using a private browser or an incognito browser. This way, we isolate this for possible browser-related. You can use either of these keyboard shortcuts:
Google Chrome: Ctrl + Shift + N
Mozilla Firefox: Ctrl + Shift + P
Safari: Command + Option + P
Once accessed, you can check your account preferences if it's set to display the service date in your sales forms. Here's how:
Go to the Gear icon.
Choose Account and Settings.
Select the Sales tab.
Click the Pencil Icon from the Sales form content section.
Toggle On the radio button for Service Date.
Click the Save button.
Hit Done.
Once completed, you can try creating your sales forms again. If it works, you'd want to clear your browser's cache so the system can start fresh. If you get the same result while using a private browser, you can try using a different browser such as Google Chrome, Microsoft Edge, or Mozilla Firefox.
Lastly, I've added these articles to help you get your way around using QuickBook: