Which version of wireshark supports decoding of 802.11k Information Elements?
Working version of Wireshark -
Version 2.4.2 (v2.4.2-0-gb6c63ae) Shows the IE and says UnDecoded
Version 2.6.1 (v2.6.1-0-g860a78b3) Shows up as Malformed
And have you tried a development version (2.9.x)? As this is a new protocol it's likely to only be supported in the most recent version.