The meaning of the alert is that the entire inventory is being sent in the email notification and isn't the sign of any issue as such.
The System inventory messages can be configured from the below document:
http://www.cisco.com/en/US/docs/unified_computing/ucs/sw/gui/config/guide/2.1/b_UCSM_GUI_Configuration_Guide_2_1_chapter_0101110.html#d123055e1411a1635
You can change the frequency of the inventory email being sent. Severity L1 is "Normal" (see the link below):
http://www.cisco.com/en/US/docs/unified_computing/ucs/sw/gui/config/guide/2.1/b_UCSM_GUI_Configuration_Guide_2_1_chapter_0101110.html#reference_7C5103B1470D4D93BEE3B39F28617BDF
Thanks,
Majid