How to soundproof toilet

last month

We have a new house and had special gib put in the walls as soundproofing behind 2 toilets, but the sound is still travelling!!

If we were to tile the walls behind the toilets, would this help?

In the main bathroom, the shower and toilet both back onto a bedroom, and with the fully tiled shower, nothing can be heard in the bedroom, but the toilet can be (and it is not tiled behind the toilet)

Looking forward to any suggestions