ttyd problem on Raspberry Pi 2 Debian 13, no login prompt

[ObjectsAndMore]

I have the following problem with ttyd on a Raspberry Pi 2 (32bit): when I run ...

ttyd.armhf -W login

... and access http://myinternalip:7681 there is no "login" prompt, just a plain cursor prompt, no other output. Yet it appears that the login procedure is actually present, because when I (blindly) enter username <return> password <return>, a new session is apparently established (as verified with the "w" command from another session); a new /dev/pts device is created, and it is removed again when I (blindly) type "exit". But this session is obviously of not much use, as there is no visible input/output on the screen.

(Note: I had to add the ttyd user to the "tty" group in /etc/group to avoid access errors in /dev/pts)

What I also tried, with no success:

-     sudo ttyd.armhf -W login
-     ttyd.armhf -W /usr/bin/login

What does work, however, is skipping the login procedure (with an entry point directly into bash) like so:

ttyd.armhf -W bash

i.e. I get a proper shell prompt and can see all input/output on the screen. But this approach is clearly not feasible for a server publicly accessible on my network. However, it proves that the armhf build of ttyd is generally working. I only have limited knowledge of how pseudo terminals work, but my gut feeling is that the shell I/O is not properly bound to the /dev/pts device.

Version details:

ttyd version 1.7.7-40e79c7
Raspbian 13 "trixie"
("Lite" install, no GUI)
kernel 6.12.47+rpt-rpi-v7

I also have another ttyd installation running on a Raspberry Pi 5 which works just fine in login mode. So, I wonder what the key difference is between these 2 configurations.

Version details of the known good configuration:

Raspberry Pi 5 (64bit)
ttyd version 1.7.7-40e79c7
Debian 12 "bookworm"
(full Desktop install)
kernel 6.6.31+rpt-rpi-2712

Any ideas? Does this sound like a software problem in ttyd or more like a Debian configuration issue?
Any hints would be greatly appreciated.