For questionnaires with filters, it is possible that the percentage value in the progress bar does not correspond to what you would expect. EFS does obviously not know in advance which answers the participant will give during the session. Therefore. the values of the progress indicator are calculated by an estimation algorithm.
You can deactivate the automatic calculation of the progress bar and set the values manually. To do this, go to Layout > Professional Editor > Progress bar and deactivate "Calculate progress automatically". Now you are able to indirectly define a value for the progress bar for each page by changing the numbers accordingly.
Further information can be found here.