[Pkg-shadow-devel] /etc/limits: "Invalid limit string:"

[Frédéric L. W. Meunier]

Slackware -current moved from 4.0.3 to 4.1.4.2 in the last days. 
Here, I noticed that login returned

login[551]: Invalid limit string: ' C20480 U300'

$ ulimit -u
300

$ ulimit -c
0

/etc/limits:

fredlwm C20480 U300

Is there anything wrong with the syntax ?

BTW, Slackware doesn't use PAM.