diff --git a/marker/providers/pdf.py b/marker/providers/pdf.py
index c0a0dff7..079ff6ee 100644
--- a/marker/providers/pdf.py
+++ b/marker/providers/pdf.py
@@ -129,9 +129,10 @@ def pdftext_extraction(self) -> ProviderPageLines:
                         font_name = span["font"]["name"] or "Unknown"
                         font_weight = span["font"]["weight"] or 0
                         font_size = span["font"]["size"] or 0
+                        polygon = PolygonBox.from_bbox(span["bbox"], ensure_nonzero_area=True)
                         spans.append(
                             SpanClass(
-                                polygon=PolygonBox.from_bbox(span["bbox"]),
+                                polygon=polygon,
                                 text=span["text"],
                                 font=font_name,
                                 font_weight=font_weight,
@@ -143,9 +144,10 @@ def pdftext_extraction(self) -> ProviderPageLines:
                                 text_extraction_method="pdftext"
                             )
                         )
+                    polygon = PolygonBox.from_bbox(line["bbox"], ensure_nonzero_area=True)
                     lines.append(
                         ProviderOutput(
-                            line=LineClass(polygon=PolygonBox.from_bbox(line["bbox"]), page_id=page_id),
+                            line=LineClass(polygon=polygon, page_id=page_id),
                             spans=spans
                         )
                     )
diff --git a/marker/renderers/markdown.py b/marker/renderers/markdown.py
index edb1ead5..0e0f2f80 100644
--- a/marker/renderers/markdown.py
+++ b/marker/renderers/markdown.py
@@ -1,3 +1,5 @@
+import re
+
 import regex
 from markdownify import MarkdownConverter
 from pydantic import BaseModel
@@ -5,6 +7,11 @@
 from marker.renderers.html import HTMLRenderer
 from marker.schema.document import Document
 
+def cleanup_text(full_text):
+    full_text = re.sub(r'\n{3,}', '\n\n', full_text)
+    full_text = re.sub(r'(\n\s){3,}', '\n\n', full_text)
+    return full_text
+
 
 class Markdownify(MarkdownConverter):
     def __init__(self, paginate_output, page_separator, **kwargs):
@@ -55,6 +62,7 @@ def __call__(self, document: Document) -> MarkdownOutput:
             sup_symbol="<sup>",
         )
         markdown = md_cls.convert(full_html)
+        markdown = cleanup_text(markdown)
         return MarkdownOutput(
             markdown=markdown,
             images=images,
diff --git a/marker/schema/blocks/equation.py b/marker/schema/blocks/equation.py
index ef320839..08caf707 100644
--- a/marker/schema/blocks/equation.py
+++ b/marker/schema/blocks/equation.py
@@ -10,7 +10,7 @@ class Equation(Block):
 
     def assemble_html(self, child_blocks, parent_structure=None):
         if self.latex:
-            return f"<p><math>{html.escape(self.latex)}</math></p>"
+            return f"\n<p><math>{html.escape(self.latex)}</math></p>\n"
         else:
             template = super().assemble_html(child_blocks, parent_structure)
             return f"<p>{template}</p>"
diff --git a/marker/schema/groups/page.py b/marker/schema/groups/page.py
index 055d7590..1f216612 100644
--- a/marker/schema/groups/page.py
+++ b/marker/schema/groups/page.py
@@ -133,6 +133,7 @@ def identify_missing_blocks(
             else:
                 new_blocks.append(new_block)
                 new_block = [(line_idx, provider_outputs[line_idx])]
+            assigned_line_idxs.add(line_idx)
         if new_block:
             new_blocks.append(new_block)
 
@@ -200,7 +201,7 @@ def merge_blocks(
         assigned_line_idxs = set()
         block_lines = defaultdict(list)
         for line_idx, provider_output in enumerate(provider_outputs):
-            if line_idx in max_intersections and max_intersections[line_idx][0] > 0.0:
+            if line_idx in max_intersections:
                 block_id = max_intersections[line_idx][1]
                 block_lines[block_id].append((line_idx, provider_output))
                 assigned_line_idxs.add(line_idx)
diff --git a/marker/schema/polygon.py b/marker/schema/polygon.py
index 0cd53074..494d7473 100644
--- a/marker/schema/polygon.py
+++ b/marker/schema/polygon.py
@@ -184,5 +184,9 @@ def merge(self, others: List[PolygonBox]) -> PolygonBox:
         return PolygonBox(polygon=corners)
 
     @classmethod
-    def from_bbox(cls, bbox: List[float]):
+    def from_bbox(cls, bbox: List[float], ensure_nonzero_area=False):
+        if ensure_nonzero_area:
+            bbox = list(bbox)
+            bbox[2] = max(bbox[2], bbox[0] + 1)
+            bbox[3] = max(bbox[3], bbox[1] + 1)
         return cls(polygon=[[bbox[0], bbox[1]], [bbox[2], bbox[1]], [bbox[2], bbox[3]], [bbox[0], bbox[3]]])
diff --git a/marker/schema/text/span.py b/marker/schema/text/span.py
index cf9b77ca..f40ecca5 100644
--- a/marker/schema/text/span.py
+++ b/marker/schema/text/span.py
@@ -9,7 +9,6 @@
 
 
 def cleanup_text(full_text):
-    full_text = re.sub(r'\n{3,}', '\n\n', full_text)
     full_text = re.sub(r'(\n\s){3,}', '\n\n', full_text)
     full_text = full_text.replace('\xa0', ' ') # Replace non-breaking spaces
     return full_text