If you have recommender enabled for a size chart, by default, the app will also inject a "what's my size" link, which will open the recommender tab directly. The link also changes content depending on when a recommendation is made. As you can see in the following screenshot, there are three states of the button.
If you wish to remove this, go to Styles & Settings, click the "Recommender" tab, then the "Display" sub-tab.
Then, in the "Recommender injection selector" section, set Position to "Do not inject".