It would seem the config file needs to be corrected in the build. So this will need reapplied after a reboot.
Ive seen this on 20.1R1-S3.3 and 20.2R1-S2.1
Here is my quick fix.
run start shell user root
cd /var/etc
vi ttys
ttyu0 "/usr/libexec/getty std" vt100 on secure
ttyu1 "/usr/libexec/getty std" unknown on secure
ttyu2 "/usr/libexec/getty 3wire" vt100 onifconsole secure
ttyu3 "/usr/libexec/getty 3wire" vt100 onifconsole secure
ttyu4 "/usr/libexec/getty 3wire" vt100 onifconsole secure
ttyu5 "/usr/libexec/getty 3wire" vt100 onifconsole secure
ttyu1 "/usr/libexec/getty std" unknown on secure
!!! Delete the duplicate of ttyu1 at the bottom
:wg write quite and now restart the getty process
kill -HUP 1
JUST making note.. On my other 2300-c-12p my ttys looks like this
Only two lines.
ttyu0 "/usr/libexec/getty 3wire" vt100 on secure
ttyu1 "/usr/libexec/getty 3wire" unknown on secure
