Adding custom PKCS12 certificate through configure client-side TLS certificate does not load after app is closed and relaunched.

When connecting to a secured Nextcloud server using a custom SSL certificate, I am able to add my PKCS12 certificate to the client through the Configure client-side TLS certificate when setting up Nexcloud Client through the flatpak. This allows me to securly connect to the Nextcloud server as expected.
Though upon reboot of my machine or just through simply closing and reopening the app, I am prompted with the warning that the SSL certificate is unknown and the only way to proceed and use Nextcloud client after this is to trust the unknown certficate.
I believe that when adding my PKCS12 certificate, it is not being stored in persisstant storage, and when the client is closed or the machine is rebooted, the PKCS12 certificate I added is no longer there.