All my consoles have quick-edit enabled. With v20, when I recall a command (up-arrow) QE is turned off for as long as the recalled command remains UNALTERED on the command line. Here are two pics of the same console. The first is normal ... just started. The second is after pressing up-arrow.
Yes, it's new to v20. WinDbg shows that when <Up> is pressed, TCC calls SetConsoleMode() with mode 0x0110. Previous versions don't call SetConsoleMode() in this situation. That's a rather peculiar mode, apparently a combo of the undocumented ENABLE_AUTO_POSITION (0x0100) and ENABLE_MOUSE_INPUT (0x0010); that'll surely clobber QE. After that, any other keystroke produces a call to SetConsoleMode() with mode 0xC7 (normal here, including ENABLE_EXTENDED_FLAGS, 0x80 and ENABLE_QUICK_EDIT, 0x40).