Is the Shimano TX-505-8 rear hub compatible with 11-speed cassettes?
Shimano says the Tourney level TX-505-8 hub is compatible with 8-10 speed cassettes.
Mountain bike 11 speed cassettes fit in on a '10 speed' freehub, because the larger inner sprockets can extend off the inner end of the freehub and not interfere with the hub and spokes. On road bikes where cassettes have narrower ranges and smaller inner sprockets the freehub has to be wider (although some wider range road cassettes do fit on 10 speed freehubs).
So, an 11 speed cassette should fit on this hub. It may be installed incorrectly. Did you put any kind of spacer on the freehub with the cassette?