I am having this same issue. I have a very large document, about 25k pixels in height. At the top of the document the text tool works flawlessly. However any paragraph text layers created too low on the image, whether I copy a text layer or create a new one, show no cursor nor highlighting of the text.
I have 64GB of RAM and a 3TB scratch disk, my main disk is SSD so I shouldn't have any memory issues. I've spent several hours trying to reset tools, presets, etc. with no success.