SSHException: Invalid packet blocking when using invoke_shell

The following code produces an exception in paramiko 2.4.2 on Xubuntu 18.04 x86-64, python 3.6.7

import paramiko
from paramiko.client import SSHClient
c = SSHClient()
c.set_missing_host_key_policy(paramiko.AutoAddPolicy())
c.connect('10.0.0.10', username='root', password='password')
x = c.invoke_shell()
x.exec_command('ls')

Traceback (most recent call last):
  File "/home/iling/.local/lib/python3.6/site-packages/paramiko/transport.py", line 1982, in run
    ptype, m = self.packetizer.read_message()
  File "/home/iling/.local/lib/python3.6/site-packages/paramiko/packet.py", line 451, in read_message
    raise SSHException("Invalid packet blocking")
paramiko.ssh_exception.SSHException: Invalid packet blocking

However, if I use send() and recv() instead of exec_command() then it works properly. I have tried many different hosts running different versions of different SSH servers (openssh, dropbear), but I still get this exception, so it is not a server issue. Some servers use bash for the shell, others use ash (busybox).

Reproduce the snippet with Paramiko 2.4.2, then inspect transport.py around Transport.run and packet.py around Packetizer.read_message, which appear in the traceback. Check how invoke_shell and exec_command interact and look for existing tests covering channel command execution; done means the reported exception is understood and the intended behavior has regression coverage.