In order to stop this from happening, follow the steps below:
Open a new email.
Click on the blue arrow on the right-hand side.
Then right-click on the blue-arrow.
Deselect the "Expand on Entry of Email body".
The change will apply instantly.
If you are still experiencing this issue, please ask a question in the MyAccess Portal Digital Assistant and ask to "Speak to a human" to be put through directly to our support team.