My appcenter not showing Trending & always showing same 2 apps on Recently Updated

Question

Somehow my appcenter broken since 1 month or so. Appcenter not showing Trending & always showing same 2 apps on Recently Updated. Is there a way to fix this without reinstalling Elementary OS? Is this bug related with my problem?: https://bugs.launchpad.net/ubuntu/+source/appstream/+bug/1848387

~ $ dpkg-query --showformat='${Package}:\t${Version}\n' --show appstream appcenter appstream-data-pantheon
appcenter:  3.2.1+r2106+pkg83~ubuntu5.0.1
appstream:  0.12.9-1+elementary11~ubuntu5.1.1
appstream-data-pantheon:    5.0-0+r82~ubuntu5.1.1
 ~ $ head -2 /etc/os-release
NAME="elementary OS"
VERSION="5.1 Hera"
 ~ $ 

Appcenter terminal output:

$ io.elementary.appcenter

** (io.elementary.appcenter:4997): CRITICAL **: 00:59:45.701: PackageKitBackend.vala:163: Unable to add data: MDB_BAD_VALSIZE: Unsupported size of key/DB name/data, or wrong DUPFIXED size

** (io.elementary.appcenter:4997): WARNING **: 00:59:46.165: FlatpakBackend.vala:448: Errors found in flatpak appdata, some components may be incomplete/missing: Unable to add data: MDB_BAD_VALSIZE: Unsupported size of key/DB name/data, or wrong DUPFIXED size

** (io.elementary.appcenter:4997): CRITICAL **: 00:59:56.557: PackageKitBackend.vala:163: Unable to add data: MDB_BAD_VALSIZE: Unsupported size of key/DB name/data, or wrong DUPFIXED size

** (io.elementary.appcenter:4997): WARNING **: 01:00:00.644: FlatpakBackend.vala:448: Errors found in flatpak appdata, some components may be incomplete/missing: Unable to add data: MDB_BAD_VALSIZE: Unsupported size of key/DB name/data, or wrong DUPFIXED size

Trying to re-install appstream-data:

$ sudo apt install --reinstall appstream-data-pantheon appstream-data-pantheon-icons appstream-data-pantheon-icons-hidpi
Paket listeleri okunuyor... Bitti
Bağımlılık ağacı oluşturuluyor       
Durum bilgisi okunuyor... Bitti      
0 paket yükseltilecek, 0 yeni paket kurulacak, 3 paket yeniden kurulacak, 0 paket kaldırılacak ve 0 paket yükseltilmeyecek.
498 kB arşiv dosyası indirilecek.
Bu işlem tamamlandıktan sonra 0 B ek disk alanı kullanılacak.
İndir: 1 http://ppa.launchpad.net/elementary-os/stable/ubuntu bionic/main amd64 appstream-data-pantheon all 5.0-0+r82~ubuntu5.1.1 [197 kB]
İndir: 2 http://ppa.launchpad.net/elementary-os/stable/ubuntu bionic/main amd64 appstream-data-pantheon-icons all 5.0-0+r82~ubuntu5.1.1 [205 kB]
İndir: 3 http://ppa.launchpad.net/elementary-os/stable/ubuntu bionic/main amd64 appstream-data-pantheon-icons-hidpi all 5.0-0+r82~ubuntu5.1.1 [96,4 kB]
1 sn.'de 498 kB alındı (418 kB/s)                             
(Veritabanı okunuyor ... 181951 dosya veya dizin kurulu durumda.)
Paket açılacak: .../appstream-data-pantheon_5.0-0+r82~ubuntu5.1.1_all.deb ...
Paket açılıyor: appstream-data-pantheon (5.0-0+r82~ubuntu5.1.1) üzerine (5.0-0+r82~ubuntu5.1.1) ...
Paket açılacak: .../appstream-data-pantheon-icons_5.0-0+r82~ubuntu5.1.1_all.deb ...
Paket açılıyor: appstream-data-pantheon-icons (5.0-0+r82~ubuntu5.1.1) üzerine (5.0-0+r82~ubuntu5.1.1) ...
Paket açılacak: .../appstream-data-pantheon-icons-hidpi_5.0-0+r82~ubuntu5.1.1_all.deb ...
Paket açılıyor: appstream-data-pantheon-icons-hidpi (5.0-0+r82~ubuntu5.1.1) üzerine (5.0-0+r82~ubuntu5.1.1) ...
Ayarlanıyor: appstream-data-pantheon (5.0-0+r82~ubuntu5.1.1) ...
Ayarlanıyor: appstream-data-pantheon-icons (5.0-0+r82~ubuntu5.1.1) ...
Ayarlanıyor: appstream-data-pantheon-icons-hidpi (5.0-0+r82~ubuntu5.1.1) ...
Tetikleyiciler işleniyor: appstream (0.12.9-1+elementary11~ubuntu5.1.1) ...
dpkg: hata: '/usr/share/app-info/yaml /usr/share/app-info/icons' sürümünü hatalı söz dizimine sahip: sürüm dizgisinde boşluk karakterleri var
(null)
 ~ $

My appstream status:

$ sudo appstreamcli status
AppStream Durumu:
Sürüm: 0.12.9

Dağıtım üst verisi:
 /usr/share/app-info
  - YAML: 2
  - Simge Kümeleri:
     elementary-bionic-extra
     elementary-stable-bionic-main

 /var/lib/app-info
  - YAML: 11
  - Simge Kümeleri:
     ubuntu-bionic-main
     ubuntu-bionic-universe
     ubuntu-bionic-multiverse
     appcenter-bionic-main
     ubuntu-bionic-security-main
     ubuntu-bionic-updates-main
     ubuntu-bionic-security-universe
     ubuntu-bionic-security-multiverse
     ubuntu-bionic-updates-universe
     ubuntu-bionic-updates-multiverse
     ubuntu-bionic-backports-universe

 /var/cache/app-info
  - Boş.

Üst veri dosyaları:
  - 62 bileşen bulundu.
  - Eski veriyollarında 8 bileşen bulundu.

Özet: Error while loading the metadata pool: Unable to add data: MDB_BAD_VALSIZE: Unsupported size of key/DB name/data, or wrong DUPFIXED size
 ~ $

Answer 1

Apparently this is a appstream package bug. And resolved. Developer of appstream is explained very well.

Related issue reports:

• https://github.com/elementary/triage/issues/6
• https://github.com/ximion/appstream/issues/264

Answer 2

sudo apt remove --purge appcenter appstream

sudo apt install appcenter