I have done some testing of this and I'm finding that all of my records are getting updated. In my test I was using DW CS3 with DataAssist 2.0.6.
I tried this two ways, the first way I did this was just like you have noted and used the DW repeat region around the tr.
I then tried this again but used the DataAssist Repeat Selection server behavior and I got the same result that way. I would like you to do one more test of this, try the same thing but instead of using the DW repeat region try using the DataAssist Repeat Selection. If you get the same result I will open a ticket for you so we can look into this further.
