Sometimes you need or want to downgaden a flatpak. Enter in the terminal:
flatpak remote-info --log flathub org.kde.kdenlive
The checksums then appear with the commit (an eternally long combination of numbers and letters).
Then select one and see if the downgrade is sufficient, if not, then select the next one below until the flatpak works properly.
In my case it is the following number and enter it like this:
sudo flatpak update --commit=1cb1ee7399bfe45491b57fc56df5999a2e1f93ba9fea76c664b87116d821f0c6 org.kde.kdenlive
(this is from the date: 2024-04-30 and results is the Kdenlive version 24.05.2)