merge leads to jumbled attribute data

Discussion created by malonzo47 on Nov 26, 2013

I am having an issue (that seems like a bug) with Merge. I have a shapefile for west TX containing about 450k polygons (result of interesection of census blocks and several other layers). I have a similar one for east TX. I want to merge them together. I run Geoprocessing-->Merge. I input the two datasets and set an output. I do not adjust any field mappings. These two inputs have identical fields. 

The problem: There are thousands of result polygons that contain attribute information for an entirely different polygon. Pre-merge intersected polygons are correct. Post-merge polygons are not. I am at a loss.  Any thoughts? Is this a known issue with a work-around?

Edit:  REALLY WEIRD: if I use the info tool multiple times one-after-another on one of the bad polygons that resulted from the merge, I get new attribute data each time. More specifically, some of the attributes increment (StateFIPs increments by 10 each click).  Has to be a bug!