Hi Keith – this is an odd one. It appears when the Feb 2019 index was created (and a couple of other months looking at it) the wrong month and year number was added https://github.com/k0711/keithfrankish-twitter/commit/248ea6138b0bf7760778bd2913f5ceb160e6f133#diff-60302947636109b0df62592939d91843
It appears all the tweet data is there correctly in your archive and all you need to do is manually edit the following file https://github.com/k0711/keithfrankish-twitter/blob/master/data/js/tweet_index.js (when logged in to github you can edit the file online – there are a couple of bad years and months so you might want to check the entire file)
Looking at why this happened for February 2019 it was because the first thing you tweeted that month was a RT from April 2018 https://twitter.com/amiguello1/status/987076270352752646.
I’ve pushed an update to the code that should prevent this happening in the future