Find does not honour parameter textLoc

Dear friends with the sharp eyes and clear thoughts:

I'm puzzled. I have this piece of code (get the full script and the test document from here😞

  foundTR = oDoc.Find(tloc, oFindParams); // find footnote anchor (FN ref)
  while (foundTR.beg.obj.ObjectValid()) {  
    oFnTI = oDoc.GetTextForRange (foundTR, Constants.FTI_FnAnchor);
    for (k = 0; k < oFnTI.length; k++) { // k always 0 nevertheless loop necessary!
      oTL   = oFnTI.obj.TextLoc;      // Location of the footnote anchor (beg)
$.writeln ("¶ format; FN ref: " + oTL.obj.Name +"; "+ oObject.FnAnchorString);
$.bp(true);
      if (CheckXRef (oDoc, oTL, sXRefFmt)) { // is there an XRef prior to FN anchor?
        tloc = oTL;
        tloc.offset += 2;                // behind the FN ref
        break; // continue;              // already an XRef inserted
      } else {
        $.writeln("\tNew FN found\n");
      }
    }
    foundTR = oDoc.Find(tloc, oFindParams); 
    oDoc.TextSelection = foundTR;        // DEBUG
  }

I have text constructs like this:

• Left to the cursor is a cross reference to the footnote; right to the cursor is the footnote anchor (FN ref).
• Before I insert the XRef, tloc points to the FN reference.
• After inserting the XRef and applying character format hypertext to the whole construct tloc points after the FN reference.
• It turns out that the Find operation (line 16) does not start at this location but at the old location which of course is now more to the left.
• Hence I'm stuck in a loop with finding the first occurrence of a footnote anchor.

Status of the Data Browser is when I am on line 17 of the above snippet:

• It can be seen that oTL gets the same offset as tloc (assigning an object just creates an alias), but really cloning the object does not help.
• Replacing break by continue (to run also the useless second iteration of the k-loop) does not have any influence, because oFnTI.length is always 1.
• Nevertheless the k-loop is necessary: oFnTI[0].obj.TextLoc is an invalid object.
• But «what withholds You than to mourn for him? [Shakepeare, Marc Antonys speech on Cesar's funeral] - What withholds Find to work properly here?
• From the FDK documentaition I learn: «FS_FindWrap :  A BoolT flag that determines whether the find operation will wrap when it reaches the location where the search began. Default is True; the find operations wraps.» Hence it is useless in my circumstances where I work towards the end of the document.
• Inserting at line 16: $.writeln ("Error " + FA_errno); // -65: FE_BadInsertPos; -41: FE_NotTextObject reports 0.

Wo liegt der hund begraben?