FieldConvert filter incorrect boundary pressure values

Hi,

I have noticed some strange behaviour with the fieldconvert filter for the latest version of nektar++, commit f6acbc41.

I am using the fieldconvert filter to generate surface data:

<FILTERS>
      <FILTER TYPE="FieldConvert">
         <PARAM NAME="OutputFile">surface.vtu</PARAM>
         <PARAM NAME="OutputFrequency">1</PARAM>
         <PARAM NAME="Modules"> extract:bnd=0 </PARAM>
      </FILTER>
</FILTERS>

The resulting pressure values are all zero for all time steps (except for the first one). When using the standalone fieldconvert application this issue does not appear.

I have attached a session file to replicate the problem - I have slightly modified the cylinder case from the tutorials.

Cylinder-Base.xml