[racket-dev] SIGSEGV MAPERR si_code 1 fault on addr 0x18

Using racket v5.2.0.2 or v5.2.0.5 (I haven't tried any others) dies with

SIGSEGV MAPERR si_code 1 fault on addr 0x18
Aborted

When I:

racket main.rkt ;;Works fine
CTR-C ;;(to kill server)
racket multi-servlet.rkt
visit URL http://localhost:8080/second.rkt
visit URL http://localhost:8080/second
visit URL http://localhost:8080/second.rkt
CTR-C 
racket main.rkt ;;immediately dies with above message

It seems that visiting those urls, in that order, is significant...

I'm guessing that there is a bug, or something that needs protected
better, or there may be some cache that I should be deleting?

The only thing I've found that gets racket main.rkt working again is to
recompile racket...

Thanks!
Jordan