Premiere mixing letters in text sequence

Hi,

I'm having big trouble trying to get this animated typewriter effect to work on my Premiere Pro CC 2018.
I get as far as the first two letters and then when I go to type the 3rd letter - instead of following on after the 2nd letter, it decides to write the 3rd letter in-between the 1st & 3rd letters - I've been messing around with this for 2 hours or more and it's driving me crazy!!
I see lots of other peeps have had the same issues! Any suggestions?