diff --git a/.github/ISSUE_TEMPLATE/bug_report.yml b/.github/ISSUE_TEMPLATE/bug_report.yml
index 957298f..b228d6e 100644
--- a/.github/ISSUE_TEMPLATE/bug_report.yml
+++ b/.github/ISSUE_TEMPLATE/bug_report.yml
@@ -1,6 +1,6 @@
 name: Bug Report
 description: |
-  Create a bug report for pdf2docx
+  Create a bug report for pdf2docx.
   Please use English only in posts and issues to aid maintainers and benefit all users. We will immediately reject and close non-English posts.
 
 # We omit `title: "..."` so that the field defaults to blank. If we set it to
diff --git a/pdf2docx/table/Cell.py b/pdf2docx/table/Cell.py
index cff0124..1b7d421 100644
--- a/pdf2docx/table/Cell.py
+++ b/pdf2docx/table/Cell.py
@@ -76,7 +76,7 @@ def make_docx(self, table, indexes):
         n_row, n_col = self.merged_cells
         i, j = indexes
         docx_cell = table.cell(i, j)
-        if n_row*n_col!=1:
+        if n_row*n_col != 1 and ((i+n_row-1) * table._column_count + j+n_col-1) < len(table._cells): # check whether index is over length of cells
             _cell = table.cell(i+n_row-1, j+n_col-1)
             try:
                 docx_cell.merge(_cell)
@@ -133,7 +133,8 @@ def _set_style(self, table, indexes):
         # merged cells are assumed to have same borders with the main cell
         for m in range(i, i+n_row):
             for n in range(j, j+n_col):
-                docx.set_cell_border(table.cell(m, n), **kwargs)
+                if len(table._cells) > m * table._column_count + n: # check whether index is over length of cells
+                    docx.set_cell_border(table.cell(m, n), **kwargs)
 
         # ---------------------
         # cell bg-color
diff --git a/pdf2docx/table/Row.py b/pdf2docx/table/Row.py
index e1a442c..2dde91e 100644
--- a/pdf2docx/table/Row.py
+++ b/pdf2docx/table/Row.py
@@ -66,7 +66,10 @@ def make_docx(self, table, idx_row:int):
         # to control the layout precisely, set `exact` value, rather than `at least` value
         # the associated steps in MS word: Table Properties -> Row -> Row height -> exactly
         docx_row.height_rule = WD_ROW_HEIGHT.EXACTLY
-        
+
+        if self.height < 0: # to prevent negative height validation
+            self.height = 0
+
         # NOTE: row height is counted from center-line of top border to center line of bottom border
         docx_row.height = Pt(self.height)
 
diff --git a/pdf2docx/text/Lines.py b/pdf2docx/text/Lines.py
index 20b5ae9..b97a33a 100644
--- a/pdf2docx/text/Lines.py
+++ b/pdf2docx/text/Lines.py
@@ -60,6 +60,9 @@ def split_vertically_by_text(self, line_break_free_space_ratio:float, new_paragr
         '''
         rows = self.group_by_physical_rows()
 
+        for row in rows:
+            row.sort_in_line_order() # sort lines in row
+
         # skip if only one row
         num = len(rows)
         if num==1: return rows