The WWAN interface check cronjob script is installed once a WWAN interface is added to the system.
Mar 27 10:50:01 LR1.wue3 CRON: (root) CMD (/usr/libexec/vyos/vyos-check-wwan.py)
If a WWAN interface is disabled, the script is called by cron but exits early due to the disabled state. Unfortunately if all WWAN interfaces are removed thw script is not vacuumed. Its not a bug, just eye candy and less spammed logs (once every 5 Minutes)