Dictation auto correcting to something wrong.

Hi MikeJ1066,

Let's have you try disabling Dictation, restarting your device, and enabling Dictation again. See: Dictate text on iPhone

Turn on Dictation

Go to Settings  > General > Keyboard.

Turn on Enable Dictation.

Try out Dictation to see if this helps resolve the issue you're facing.

Take care.

Hello MikeJ1066,

Thank you for reaching out to Apple Support Communities, and we'll be happy to help in any way we can. We understand you're having issues with Dictation. Follow the steps listed here to resolve the issue: Use Dictation on your iPhone, iPad, or iPod touch

"If dictation isn’t sure what word it heard, you'll see a blue line under the transcribed word so you can check it for accuracy. To make corrections, tap the underlined word, then select the correct spelling. To replace a word, double-tap it, tap the microphone button , then say it again, and tap the keyboard button . 

To replace a section, select what you want to replace, then tap the microphone button  and speak again. To add more text, tap where you want to add new text, tap the microphone button , then speak again."

We hope this helps.

Cheers!