The same bug affects me with 4.6. I do not remember the last time I used Qarte so I do not know for how log it occurs.

> qarte -d
16:48:24: INFO - qarte Qarte-4.6.0
16:48:24: INFO - qarte Python 3.7.6 on Linux-5.3.0-3-amd64-x86_64-with-debian-bullseye-sid
16:48:24: INFO - qarte File system encoding: utf-8
16:48:24: INFO - qarte System encoding: utf-8
16:48:24: INFO - qarte Locale encoding: ('fr_FR', 'UTF-8')
16:48:24: INFO - core Set workspace
16:48:24: INFO - core Load config from: /home/me/.Qarte/user_config
16:48:24: INFO - core Build main window
16:48:24: INFO - artetv Fetch page: https://www.arte.tv/fr/guide/20200116/
16:48:24: WARNING - artetv Read json error: Extra data: line 1 column 131305 (char 131304)
16:48:24: WARNING - artetv Begin: {"alternateLanguages
16:48:24: WARNING - artetv listing_TV_GUIDE NOT FOUND
16:48:24: INFO - artetv Fetch page: https://www.arte.tv/fr/guide/20200117/
16:48:24: WARNING - artetv Read json error: Extra data: line 1 column 132995 (char 132994)
16:48:24: WARNING - artetv Begin: {"alternateLanguages
16:48:24: WARNING - artetv listing_TV_GUIDE NOT FOUND
16:48:24: INFO - artetv Sorting videos
16:48:24: INFO - artetv Fetch page: https://www.arte.tv/fr/guide/20200118/
16:48:25: WARNING - artetv Read json error: Extra data: line 1 column 127459 (char 127458)
16:48:25: WARNING - artetv Begin: {"alternateLanguages
16:48:25: WARNING - artetv listing_TV_GUIDE NOT FOUND
16:48:25: INFO - artetv Sorting videos
16:48:25: INFO - artetv Fetch page: https://www.arte.tv/fr/guide/20200119/
16:48:25: WARNING - artetv Read json error: Extra data: line 1 column 129942 (char 129941)
16:48:25: WARNING - artetv Begin: {"alternateLanguages
16:48:25: WARNING - artetv listing_TV_GUIDE NOT FOUND
16:48:25: INFO - artetv Sorting videos
16:48:25: INFO - artetv Fetch page: https://www.arte.tv/fr/guide/20200120/
16:48:25: WARNING - artetv Read json error: Extra data: line 1 column 112710 (char 112709)
16:48:25: WARNING - artetv Begin: {"alternateLanguages
16:48:25: WARNING - artetv listing_TV_GUIDE NOT FOUND
16:48:25: INFO - artetv Sorting videos
16:48:25: INFO - artetv Fetch page: https://www.arte.tv/fr/guide/20200121/
16:48:25: WARNING - artetv Read json error: Extra data: line 1 column 129973 (char 129972)
16:48:25: WARNING - artetv Begin: {"alternateLanguages
16:48:25: WARNING - artetv listing_TV_GUIDE NOT FOUND
16:48:25: INFO - artetv Sorting videos
16:48:25: INFO - artetv Fetch page: https://www.arte.tv/fr/guide/20200122/
16:48:25: WARNING - artetv Read json error: Extra data: line 1 column 115768 (char 115767)
16:48:25: WARNING - artetv Begin: {"alternateLanguages
16:48:25: WARNING - artetv listing_TV_GUIDE NOT FOUND
16:48:25: INFO - artetv Sorting videos
16:48:25: INFO - artetv Fetch page: https://www.arte.tv/fr/guide/20200123/
16:48:25: WARNING - artetv Read json error: Extra data: line 1 column 127721 (char 127720)
16:48:25: WARNING - artetv Begin: {"alternateLanguages
16:48:25: WARNING - artetv listing_TV_GUIDE NOT FOUND
16:48:25: INFO - artetv Sorting videos
16:48:25: INFO - artetv Fetch page: https://www.arte.tv/fr/guide/20200124/
16:48:25: WARNING - artetv Read json error: Extra data: line 1 column 119870 (char 119869)
16:48:25: WARNING - artetv Begin: {"alternateLanguages
16:48:25: WARNING - artetv listing_TV_GUIDE NOT FOUND
16:48:25: INFO - artetv Sorting videos
16:48:25: INFO - artetv Fetch page: https://www.arte.tv/fr/guide/20200125/
16:48:25: WARNING - artetv Read json error: Extra data: line 1 column 129237 (char 129236)
16:48:25: WARNING - artetv Begin: {"alternateLanguages
16:48:25: WARNING - artetv listing_TV_GUIDE NOT FOUND
16:48:25: INFO - artetv Sorting videos
16:48:25: INFO - artetv Fetch page: https://www.arte.tv/fr/guide/20200126/
16:48:25: WARNING - artetv Read json error: Extra data: line 1 column 127012 (char 127011)
16:48:25: WARNING - artetv Begin: {"alternateLanguages
16:48:25: WARNING - artetv listing_TV_GUIDE NOT FOUND
16:48:25: INFO - artetv Sorting videos
16:48:25: INFO - artetv Check thumbnails
16:48:25: INFO - artetv Thumbnails completed
16:48:25: INFO - artetv Found 0 videos in 1.2444610595703125 sec.
16:48:25: INFO - artetv Clean thumbnail folder
16:48:25: INFO - arteconcert Get update ...
16:48:26: INFO - arteconcert Concert list updated
16:48:26: INFO - arteconcert show category: Arts de la scène