In 4.2.7.8 FTWindow, the function fts:joinIncludes has the lines:

     <fts:tokenInfo
         startPos="{$minPos}"
         endPos  ="{$maxPos}"
         startSent="{fn:min($strIncls/fts:tokenInfo/@startSent)}"
         endSent  ="{fn:max($strIncls/fts:tokenInfo/@startSent)}"
         startPara="{fn:min($strIncls/fts:tokenInfo/@startPara)}"
         endPara  ="{fn:max($strIncls/fts:tokenInfo/@startPara)}"/>

I'm pretty sure the values for endSent and endPara should refer
to @endSent and @endPara, not @startSent and @startPara.
That is, it should be

         endSent  ="{fn:max($strIncls/fts:tokenInfo/@endSent)}"
         ...
         endPara  ="{fn:max($strIncls/fts:tokenInfo/@endPara)}"/>