No, 5ghz was originally bad for RB4011. On our device, everything is sad and bad. Regardless with capsman or without.
http://forum.mikrotik.com/t/rb4011-wlan1-disabling-itself/125605/1
http://forum.mikrotik.com/t/mikrotik-rb4011igs-5hacq2hnd-and-wifi-802-11ac-crash-interface/128101/1