It is certainly not normal for the IC to be rattling inside. You can either talk to MP3Car, and get it exchanged, or ship it to ScanTool.net.
Was the IC labeled "ELM327"? It has a "half-moon" on one end, as does the IC socket on the board. If you say it worked after you plugged it in, then it's in the right way.
What software are you using it with? On what type of vehicle (year/make/model)?
If you select only RPM, would it still "randomly disconnect"?