As often as I tried, no handles in a text box appeared to reshape the box.
Can you click Help > About LibreOffice then click the icon just after Version Information to copy the details. Paste the details in your question if you can still edit it (pencil icon) or a new comment.
The most likely reason you cannot access the text box handles is that the text box is in a larger group. Right click on the edge of the text box and select Enter Group F3. Depending on how many sub-groups there are you might need to enter group more than once.