Got my own $20 bill twice

While not a hit, it is not too often I get a bill back that I had spent already. This was an exception. I almost surely spent it at the place I got it though ten days or less prior. http://www.trackdollar.com/report.htm?url=BH0F974E43AEB1CA5E631BE7023E2E377758818F64&sess=00745CDCA2

I often get my $2 bills back, and sometimes I get the same Tom back yet again. I do often update user notes about the reappearance(s).
Occasionally I see my $1s again, especially from a bank where I deposited them.
Yet the $2s are circulated outside of banks first.