It is possible on my PC to install Ubuntu2104beta without encountering this behaviour and I can successfully install the Ubuntu flavour.
This bug does happen with the Kubuntu beta and I find it is impossible to install the Kubuntu flavour from the beta iso.
It is worth noting that mesa is present in both Ubuntu and Kubuntu.
It is possible on my PC to install Ubuntu2104beta without encountering this behaviour and I can successfully install the Ubuntu flavour.
This bug does happen with the Kubuntu beta and I find it is impossible to install the Kubuntu flavour from the beta iso.
It is worth noting that mesa is present in both Ubuntu and Kubuntu.