I checked out 5.2.1-rc0, did a clean build and installed fresh. I made the following changes to records.config

proxy.config.url.remap.remap_required INT 0
proxy.config.http.redirection_enabled INT 1
proxy.config.http.number_of_redirections INT 3

If I start this and do "curl --proxy localhost:8080 http://docs.trafficserver.apache.org" it crashes due to an assert.

Igor - do you have any stack traces or additional logging data in traffic.out? Are you running under load or is this without any traffic at all?