Help identify disease/issue with Tibouchina

Hi All

I have some young Tibouchina plants growing on the windowsill which are growing away fairly well. However, I’ve noticed some of the leaves are developing what look like tiny bumps/ eggs on the top surface of the leaves. Some of said leaves have then become deformed. If anyone is able to help identify what the issue is, I would be very grateful. Photos attached showing heathy leaf, leaf with small bumps and finally a deformed leaf. Thanks