Hi,
We have experienced this issue in iphones as well. What we did was use some css to undo the parallax features on mobile devices. We have a very broad setting for all mobile devices. You can of-course fine-tune with your own media queries. The logic we have used is (provided you are using a section background image):
//fix for parallax issue on mobile devices using level 4 media query hover - more info: developer.mozilla.org/en-US/docs/Web/CSS/Media_Queries/Using_media_queries#Targeting_media_features;
@media (hover: none) {
.sp-page-builder .page-content .sppb-section {
background-attachment: scroll!important;
background-position: center!important;
}
}