[Bug] The main unread article screen in not well synchronized with the FreshRSS web view

[Massedil]

Reproduce:

1. Do a full synchronization
2. Click on 1 feed in the feed list (here a feed with 68 unread items)
3. Click on the "Load more article" button (50 articles seems to be loaded, from A1 the newest to A50 the oldest)
4. Go on the "All unread articles" screen
5. The is only the 50 articles from the feed updated in step 3
6. Scroll down and click to the "Load more article" button

Actual:

The view does not correspond to the web view from FresRSS.

The new articles loaded are older than the A50 !

Expected:

The view correspond to the web view from FresRSS.

The new articles loaded are the more recent unread articles.

Logs:

1. Do a full synchronization:

GET /api/greader.php/reader/api/0/tag/list?client=android&output=json&ck=1634229965268 
GET /api/greader.php/reader/api/0/subscription/list?client=android&output=json&ck=1634229965526 
GET /api/greader.php/reader/api/0/stream/contents/?n=5&likes=false&comments=false&r=n&client=android&output=json&ck=1634229966475 
GET /api/greader.php/reader/api/0/stream/contents/?c=1634228681114764&n=50&likes=false&comments=false&r=n&client=android&output=json&ck=1634229966639 
GET /api/greader.php/reader/api/0/stream/contents/?c=1634221468602175&n=50&likes=false&comments=false&r=n&client=android&output=json&ck=1634229967239 
GET /api/greader.php/reader/api/0/stream/contents/?c=1634214248143239&n=50&likes=false&comments=false&r=n&client=android&output=json&ck=1634229967890 
GET /api/greader.php/reader/api/0/stream/contents/?c=1634205127490028&n=50&likes=false&comments=false&r=n&client=android&output=json&ck=1634229968298 
GET /api/greader.php/reader/api/0/stream/contents/?c=1634201628745664&n=50&likes=false&comments=false&r=n&client=android&output=json&ck=1634229970203 
GET /api/greader.php/reader/api/0/stream/contents/?c=1634195645048642&n=50&likes=false&comments=false&r=n&client=android&output=json&ck=1634229970908 
GET /api/greader.php/reader/api/0/unread-count?client=android&output=json&ck=1634229987481 
GET /api/greader.php/reader/api/0/stream/items/ids?s=user%2F-%2Fstate%2Fcom.google%2Freading-list&n=600&xt=user%2F-%2Fstate%2Fcom.google%2Fread&client=android&output=json&ck=1634230000017 

3. Click on the "Load more article" button:

GET /api/greader.php/reader/api/0/stream/contents/feed/801?n=50&xt=user%2F-%2Fstate%2Fcom.google%2Fread&likes=false&comments=false&r=n&client=android&output=json&ck=1634230279516

6. Scroll down and click to the "Load more article" button

GET /api/greader.php/reader/api/0/stream/contents/?nt=1633947119&n=50&xt=user%2F-%2Fstate%2Fcom.google%2Fread&likes=false&comments=false&r=n&client=android&output=json&ck=1634230493647