Workaround in the meantime is to turn off Smart Punctuation in Settings / Keyboard. I had the exact same issue, and this fixed it.
I presume that support for Smart Punctuation will be worked into the iOS11 version of NoMachine. Prompt – my preferred app for SSH – had the same issue, but just released a version that will support Smart Punctuation (i.e., translate the typographic quotes back to the basic stuff we need for UNIX terminal apps).