I’ve noticed some issues with the Instagram element when editing a page in Safari.
The image ratio does not alter the image size, and the default image is stretched outside the container in Safari
When I alter the number of posts in either Safari or Chrome it will not save the different amounts correctly. For example, if I set the number of posts for a desktop to 6 and then change the mobile to 4, the desktop amount is changed to 4 and vice versa.
The number of posts per page is not a CSS setting, so it cannot be changed per breakpoint. You can hide certain posts on specific breakpoints with custom CSS if needed.