Você precisa escapar dos caracteres percentuais usando uma barra invertida:
.../SK_ITEM_EXTRACT_MFGPRO_$(date +\%m\%d\%y).txt
Na página crontab(5) man da implementação do ISC de cron :
The ''sixth'' field (the rest of the line) specifies the command to be run. The entire command portion of the line, up to a newline or % character, will be executed by
/bin/shor by the shell specified in theSHELLvariable of the crontab file. Percent-signs (%) in the command, unless escaped with backslash (\), will be changed into newline characters, and all data after the first % will be sent to the command as standard input. There is no way to split a single command line onto multiple lines, like the shell's trailing "\".