Hiya
That IP address is used by STB's as their default gateway if they are in the same IP range as that one. It's not going to affect your PC in any way, as your PC has no visibility of that address really, your PC uses a public address, it's only used by your STB to communicate with DHCP servers, TFTP, time of day.
It's probably just router is seeing broadcast traffic and getting a bit upset about it, won't harm your system in any way, nothing to worry about whether it gets through or not, just part of the background noise on the Internet