Temporary Containers not working

I installed the Temporary Containers addon, I turned on automatic mode, but tabs new tabs are not being assigned temporary containers automatically. This works fine on my Windows version of LibreWolf, but it is not working on Linux.

I am using the LibreWolf flatpak from Discover. stable, 89.0 (64-bit).

Here is the link to the Temporary Containers addon: https://addons.mozilla.org/en-US/firefox/addon/temporary-containers/