I found what looks like a bug when using TP on Bricscad 17.2.03.
Steps to Reproduce problem
1.Create a DTEXT and edit it.
2. Insert a Field for example drawing filename.
3. Copy the dtext 2 or three times.
4. Use the Text - paragraph - restack command in TP and follow the prompt to restack the text.
5. I kept "New text height" as Unchanged , selected the first dtext as Base string.
6. I used interline scale factor 5 and then selected the other 3 dtext entities.
7. Restack worked and placed them correctly.
Error : The field in the DTEXT got converted to plain text when it should have remained as a field.