Hi,
It’s probably because of the earlier custom CSS suggestion:
[html].resdrg .asp_isotopic_item {
position: static !important;
float: right;
margin-right: 10px !important;
}[/html]
It looks like it does not work on mobile devices. If you remove it, it should start working again.
I have already contacted the isotope script developer, I’m sure he will be able to suggest a customization for RTL layouts.