As it seems, the LOC problem is in the TBM 900 - XPlane 11.50 matching.
Currently, the TBM does not support the way XPlane 11.50 manages nav data (Just LOCs, actually).
A possible workaround is using the 11.41 version of the nav data, as provided by Navigraph....
The problem is, Navigraph is going to discontinue the 11.41 data very soon.
Hopefully the coming update of the TBM from X Aviation will solve everything.
From the Navigraph forum:
"we have decided to offer the AIRAC updates till end of this year, means the last AIRAC cycle will be 2014. After this cycle, we discontinued these outdated version and will offer only the new navdata format for X-Plane 11.50 and above. AIRAC 2012 is built and uploaded. When you use the FDM, you can map X-Plane 11.41 manually. When you use the manual setups, we have created a own record for this, with the different version numbers."