This seems relevant:

When does this occur? --------------------- The issue occurs if both of the following conditions are true:

1. Either: a) You used the it2ssh command, or b) In Settings > Profiles > General, the Command popup menu was set to "SSH" (not "Login Shell", "Command", or "Custom Command") AND "SSH Integration" was checked in the SSH configuration dialog. That dialog is shown when you click the Configure button next to the ssh arguments field in Settings.

2. The remote host has Python 3.7 or later installed in its default search path.