Extracted and saved vpk with inconsistent tree_length

[invokerbyxv]

I tried to do an extraction of the VPK file and repackaged it.

def extract():
 pak1 = vpk.open("E:/Program Files (x86)/Steam/steamapps/workshop/content/570/2967026351/2967026351.vpk")
 for filepath in pak1:
 print(filepath)
 file = pak1.get_file(filepath)
 path = os.path.join("./Lost_Temple", filepath)
 directory = os.path.dirname(path)
 if not os.path.exists(directory):
 os.makedirs(directory, exist_ok=True)
 file.save(path)

def pack_vpk():
 pak = vpk.new("./Lost_Temple")
 pak.save("E:/Program Files (x86)/Steam/steamapps/workshop/content/570/2967026351/2967026352.vpk")

But when I open 2967026352.vpk using GCFSpace, I get an error: Could not open 2967026352.vpk. Invalid file: The file map is not within mapping bounds.

Then I realized that the repackaged VPK tree_length didn't match the source file.

def print_vpk():
 pak1 = vpk.open("E:/Program Files (x86)/Steam/steamapps/workshop/content/570/2967026351/2967026351.vpk")
 # 242158
 print(pak1.tree_length)
 pak2 = vpk.open("E:/Program Files (x86)/Steam/steamapps/workshop/content/570/2967026351/2967026352.vpk")
 # 242114
 print(pak2.tree_length)

Did I do something wrong?