Messages takes up a lot of space in iCloud even after deleting several Conversations

Hi all!

I recently received a message telling me that my iCloud storage (5 GB) was almost full.

I took a look at it and realized that Messages was taking up 2.9 GB of space. So yesterday, I deleted (in all my devices) several long time Conversations containing several images and videos.

I go back this morning to check my iCloud storage and it hasn't changed. Messages still takes up 2.9 GB.

Could you help me understand that situation please?

Thank you!