SQL HelpFollow

I know this is more of a hardware forum, but I was hoping to get some SQL help. I figure some of the regulars here would be familiar with SQL. It's a bizarre problem that I wouldn't even know how to properly google.

I have a temp table that I'm inserting rows into. If I perform the following script:

insert into #TempTable
select * from TableA

...I get a "String or binary data would be truncated" error. Ok, that's fine. I guess somewhere in the data there's probably a string value too large. So I checked the string fields and I'm pretty sure there are none that are too large. I verify this with some text length queries on the string columns.

So just to make sure there isn't something I miss, I attempt to insert just the top 100 records. If that works, the top 200. I figure I'll narrow down to the record that has bad data in it. And that's when I come upon something that's totally baffling.

There are 409 records in TableA. If I do this script, it works:

insert into #TempTable
select top 500* from TableA

Yet, if I do this script, it fails:

insert into #TempTable
select * from TableA

wtf? Anyone seen this before?

After some more testing, I find that the script fails when I select the top 507 rows, but it works if I select the top 506 rows. And yet, the actual row count is still only 409! So I don't even know where to begin with this.

Edit: I guess I should mention I'm working in MS SQL 2008

Edited, Nov 2nd 2010 11:59am by enigmaticcam

Probably was a glitch of some sort. I figured out the problem was the table definitions didn't match. I found some of the string fields declared in the temp table were smaller than the regular table, and this seemed to cause the problem despite the fact that none of the data was too large for either table. I still don't know why it was successful some of the time, but ultimately I fixed it by making sure it all matched exactly.