OT: Strange ARP Behavior

Has anybody else ever seen anything like this or know why this is happening?
I have R1 connected to Cat1, a L3 switch. R1 has an IP address 10.10.10.4
and Cat1 VLAN1 has an IP address of 10.10.10.1.

When I initially ping 10.10.10.1 from Cat1 of course the ARP process happens
and I end up with an ARP table entry on R1 for 10.10.10.1. However, when I
clear the arp cache via "clear arp" or "clear ip arp 10.10.10.1", R1
IMMEDIATELY sends a gratuitous ARP for it's own IP address (which is normal
and fine) but then the puzzle....it sends a UNICAST ARP request for
10.10.10.1 to the specific MAC address of Cat1 VLAN1 interface. How R1
still knows this address is the mystery.

Additional Information: R1 has no routes other than the directly connected
route. No default route, no static route, nothing. IP routing is enabled.
In my troubleshooting I disabled CEF and had the same issue. Debugs below

R1(config-if)#do sh ip arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 10.10.10.1 0 0018.1820.2740 ARPA FastEthernet0/0
<--- Cat1 VLAN1
Internet 10.10.10.4 - 0019.e721.84da ARPA FastEthernet0/0
<--- R1 Fa0/0

R1(config-if)#do clear arp
R1(config-if)#

/* GRATUITOUS ARP -- Normal */
*Jun 24 02:27:00.663: ARP: flushing ARP entries for all interfaces
*Jun 24 02:27:00.667: IP ARP: sent rep src 10.10.10.4 0019.e721.84da,
                 dst 10.10.10.4 ffff.ffff.ffff FastEthernet0/0

/* WTF ? /*
*Jun 24 02:27:00.667: IP ARP: sent req src 10.10.10.4 0019.e721.84da,
                 dst 10.10.10.1 0018.1820.2740 FastEthernet0/0
*Jun 24 02:27:00.667: IP ARP: rcvd rep src 10.10.10.1 0018.1820.2740, dst
10.10.10.4 FastEthernet0/0

-- 
Regards,
Joe Astorino
CCIE #24347
Blog: http://astorinonetworks.com
"He not busy being born is busy dying" - Dylan
Blogs and organic groups at http://www.ccie.net