Zebra Printers disappear from list

[MikeInLa]

Website version: 4028
Lansweeper version: 4.2.0.52
Running on: Windows XP Pro SP3
Scans one domain, multiple subnets.

Hi,
I've been using Lansweeper for nearly a year now. Today I noticed a strange issue: scanned printers show up in my list, then disappear. This appears to be happening on the same 14 printers (out of about 40 in our network). These disappearing printers are in the same subnet with about 12 others that show up and stay in the list. Interestingly enough, these printers that disappear are 3 similar models of Zebra label printers: GK420d, GX420t, and GX430t. Has anyone run across this issue with Zebra label printers dropping off the list?

[MikeInLa]

I know this may sound crazy, but it looks like it won't let me have more than ONE of the Zebra printers at a time. I can force it to scan the IP address of one of them, it detects it and adds it. When I force it to scan another IP address, it detects and adds it, but removes the last one. Very strange, and ONLY on the Zebra label printers.