[Therion] Bug in Loch Viewer 5.2.11 not showing passages with LRUD data from Survex 3d files

I have found that the latest development build of the Loch viewer does not display all the centrelines in my Survex 3d file. It looks like it is the centrelines which have LRUD data, plus legs attached to these. If I show walls then these are rendered, so only the attached legs are missing. But if I hide walls then all the passages with walls data disappear completely. See attached comparision screenshots from 5.2 and 5.2.11 with and without the walls shown. Footleg