It's still a bug in 16.4.0 and it can be immediately be reproduced when going to the Sandbox page and opening the list of attachments. The bug is in https://github.com/xwiki/xwiki-platform/blob/xwiki-platform-16.4.0/xwiki-platform-core/xwiki-platform-livedata/xwiki-platform-livedata-webjar/src/main/vue/LivedataPagination.vue#L290-L293: we add in the set of page size the actual limit coming from the query. And as soon as we select another page size, the limit change in the query and the value disappear from the set of page sizes.
