Predictive text missing for just one non Apple application

I am running a 3rd party application, for which predictive text worked fine for the last year. However, for this app (which I have also deleted and re-installed), no longer shows the predictive information when the keyboard is active. I seem to remember that I inadvertently might have "swiped it away" when entering data one day (although I am not 100% sure), but regardless, I cannot get it to re-appear permanently for this app. I should note that I can get it to temporarily appear by holding my finger on the letter I would like to have it use for the predictive function, but then it immediately disappears once a choice is made, never to re-appear. Any thoughts?