The Incremental Reading add-on currently has issues when being used at the same time as the AMBOSS - Anki add-on. In order to solve this issue, you'd need to disable the add-on. Here's how:
In Anki head to Tools > Add-ons then selected the add-on and click on Toggle Enabled on the right side. Once the add-on name turns grey, it will be disabled.
If any other add-ons that you are using are colliding with the AMBOSS Anki add-on, please reach out to us via the help icon on the bottom right of this page and we'll help you as soon as we can.