The app chooses a fingering trying to find the closest position in relation to the previous chord (the way a guitarist would do)
If you tap on a chord and choose a different voicing, the following chord choices will change accordingly but when the next chorus comes around it's not guaranteed that your chosen voicing will be back as it might no be the closest fingering at that moment.
Ideally you learn from the available choices and don't need to keep looking at every single voicing.
One suggestion would be to work on a few bars at the time, that way you have more control of which fingering are displayed.