Spring boot pagination returning same content

Question

I'm having trouble with spring boot pagination. My pagination settings are:

spring.data.web.pageable.size-parameter=size
spring.data.web.pageable.page-parameter=page
spring.data.web.pageable.default-page-size=10
spring.data.web.pageable.one-indexed-parameters=false
spring.data.web.pageable.max-page-size=20
spring.data.web.pageable.qualifier-delimiter=_

I have an endpoint that holds 2 entities, /blocked-study-groups when I call the endpoint with size=2&page=0 I of course, get both of my entities. The problem comes, when I try to fetch the entities one by one. When I call the endpoint with size=1&page=0 I get this response

{
"content": [
    {
        "id": "7LRoDdGoKVn",
        "name": "a--",
        "creator": {
            "id": "wLKQgwWQ9Ab",
            "nickname": "Giwemik",
            "email": "[email protected]",
            "avatar": "https://avatars.dicebear.com/api/bottts/a9bf5e6d-b882-412a-a31c-2bae15f90465.svg",
            "nameId": "GG7N",
            "emailNotifications": false,
            "pushNotifications": true
        }
    }
],
"pageable": {
    "sort": {
        "empty": true,
        "sorted": false,
        "unsorted": true
    },
    "offset": 0,
    "pageNumber": 0,
    "pageSize": 1,
    "paged": true,
    "unpaged": false
},
"size": 1,
"number": 0,
"sort": {
    "empty": true,
    "sorted": false,
    "unsorted": true
},
"first": true,
"last": false,
"numberOfElements": 1,
"empty": false
}

Which has the same content (not the whole response) as when I call it with size=1&page=1:

{
"content": [
    {
        "id": "7LRoDdGoKVn",
        "name": "a--",
        "creator": {
            "id": "wLKQgwWQ9Ab",
            "nickname": "Giwemik",
            "email": "[email protected]",
            "avatar": "https://avatars.dicebear.com/api/bottts/a9bf5e6d-b882-412a-a31c-2bae15f90465.svg",
            "nameId": "GG7N",
            "emailNotifications": false,
            "pushNotifications": true
        }
    }
],
"pageable": {
    "sort": {
        "empty": true,
        "sorted": false,
        "unsorted": true
    },
    "offset": 1,
    "pageNumber": 1,
    "pageSize": 1,
    "paged": true,
    "unpaged": false
},
"size": 1,
"number": 1,
"sort": {
    "empty": true,
    "sorted": false,
    "unsorted": true
},
"first": false,
"last": true,
"numberOfElements": 1,
"empty": false
}

I'm not sure if it is needed, but for the record, I also provide controller and service: Controller:

@GetMapping("/{id}/blocked-study-groups")
public Slice<StudyGroupDto> getBlockedStudyGroups(@PathVariable String id, Pageable pageable) {
    return studentService.getBlockedStudyGroups(hashidsUtil.decodeId(id), pageable);
}

Service:

public Slice<StudyGroupDto> getBlockedStudyGroups(long id, Pageable pageable) {
    Slice<StudyGroup> page = studyGroupRepository.findByBlockedById(id, pageable);
    return new SliceImpl<>(dtoMapper.mapStudyGroups(page.getContent()), page.getPageable(), page.hasNext());
}

Why do both pages display the same entity when I have 2 entities in the database?