Temporary fix is to turn off beacon colors in the EtFuturum config. I'll come up with a workaround sometime.

Furthermore, Et Futurum's skin backport breaks the Gaia Guardian render. That can also be turned off.

They also can't be summoned with Chisel beacons.

It appears that checking for TileEntityBeacon existing at that location might be more prudent, as they all use it.