Hi Min Zheng,
It sounds like from your description that the connection for table 1 got changed to use the same connection as table 2. It is possible when you open up the connected table settings to change over to a different connection for the table. Alternatively it is possible that someone put the file Backhaul Input file2.csv into the wrong file in your source location that you are syncing from, but seems less likely since rebuilding the table again with a fresh connection resolved the issue. If table 1 still existed I would suggest going into the connection settings and checking to see which connection it was using, to see if it might have been accidentally changed and then also checking the original source just to be sure nothing accidentally overlapped.
