MAC not showing up in arp list

Hi there!
   In my config, I have four LCS's defined:

  0E20.2       LCS     -o oat/oatfile.txt
  0E22.2       LCS     -o oat/oatfile22.txt
  0E24.2       LCS     -o oat/oatfile24.txt
  0E26.2       LCS     -o oat/oatfile26.txt

I'm not sure I'm doing this correctly, or that I shouldn't just have one big combined oat file or not, but this works, except the last one...  Also, this is on Linux.

My oat files look like this:

oatfile24.txt:
*********************************************************
* Dev   Mode  Port  Entry specific information...                                       *
*********************************************************

  0E24  IP    00    PRI  192.168.4.116
  HWADD       00    52-C5-72-E9-1C-57


oatfile26.txt:
*********************************************************
* Dev   Mode  Port  Entry specific information...                                       *
*********************************************************

  0E26  IP    00    PRI  192.168.4.117
  HWADD       00    52-C5-72-E9-1C-59


Each one opens up a tap interface, so I have tap0, tap1, tap2, and tap3.
I have a bridge, br0, on my wired interface:

laptop1:/root # brctl show br0
bridge name         bridge id                      STP enabled      interfaces
br0                         8000.52c572e91c55   no                       eth0
                                                                                                  tap0
                                                                                                  tap1
                                                                                                  tap2
                                                                                                  tap3

My problem is, tap3 isn't working.  On the other ones, if I do a "brctl showmacs br0", I can see that for example, it shows the MAC for tap2 that ends in 57, and the MAC that the guest OS actually uses, which ends in 58...  However, for tap3, I see the MAC ending in 59, and the guest OS reports it's using a MAC ending in 5A, but it doesn't show up in the showmacs list on the bridge.  What's more interesting is that the guest OS can see some other MACs in it's arp table, including some from other wired devices on the LAN, but yet it can't ping or be pinged.

I'm thinking the problem is related to (or a symptom of) the -5A MAC address not showing up on the bridge.

Has anyone seen any such behavior or have an idea how to debug this?

Thank you so much!!