Hey Dennjon,
We'd be happy to help out. If you're talking about the Messages app, you are correct. Regardless of whether you've split the keyboard, have it appearing as normal, or have a floating keyboard, you should always be able to see the message you're responding to, since the keyboard would appear below that message in the thread.
Perhaps try restarting your iPad if this behavior persists. If all else fails, make sure by latest iPadOS you're referring to iPadOS 16.2. If that's not what you're running, you'll find help updating here:
Update your iPhone or iPad wirelessly
1. Back up your device using iCloud or your computer.
2. Plug your device into power and connect to the internet with Wi-Fi.
3. Go to Settings > General, then tap Software Update.
4. If you see more than one software update option available, choose the one that you want to install.

5. Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do.
This is outlined further here: Update your iPhone or iPad - Apple Support
You might also want to try making an adjustment to the onscreen keyboard and then changing it back using the steps here: Adjust the onscreen and external keyboard settings on iPad - Apple Support
We hope this helps out.
Take care!