Changes impacting upload member photo

Uploading a member photo recently become unavailable on our site.
investigations uncovered the following:

On page https://mentorsforwomen.app/account clicking the edit profile button
adds a faded backdrop '

' and makes visible the modal (pop out window) id ctl01_TemplateBody_WebPartManager1_gwpciProfileimage_ciProfileimage_contactPicture_profilePictureEditModal
by changing the style="display: none;" to style="display: block;" and adding the css class 'in'
which triggers the css .fade.in { opacity: 1; } in the imis css file at https://mentorsforwomen.app/Assets/css/10-UltraWaveResponsive.css.

When the bootstrap css styling script 'https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css' we are using to style the app is active for the site the faded backdrop '

' is generated and the 'in' class added but our css overrides the code in 10-UltraWaveResponsive.css

The problem seems to arise because the core iMis solution does not appear to have used a naming convention different from Bootstrap.

It would be helpful to know what has changed in the last release that caused this issue, and how we can ensure we don't have further issues like this.