Here is the list. This seems to only happen on BYE and ACK, usually BYE for whatever reason. Out of curiosity, why were you asking about `$du` earlier rather than `$ru`? Isn't setting `$ru` what calls `pv_set_ruri()`?
``` loadmodule "jsonrpcs.so" loadmodule "kex.so" loadmodule "corex.so" loadmodule "tm.so" loadmodule "tmx.so" loadmodule "sl.so" loadmodule "rr.so" loadmodule "pv.so" loadmodule "maxfwd.so" loadmodule "usrloc.so" loadmodule "registrar.so" loadmodule "textops.so" loadmodule "siputils.so" loadmodule "xlog.so" loadmodule "sanity.so" loadmodule "ctl.so" loadmodule "cfg_rpc.so" loadmodule "acc.so" loadmodule "counters.so"
loadmodule "db_text.so" loadmodule "enum.so"
loadmodule "auth.so" loadmodule "auth_db.so"
loadmodule "alias_db.so"
loadmodule "nathelper.so" loadmodule "rtpproxy.so"
loadmodule "tls.so" ```
I've reverted back to 5.2.4 for the time being, but could have another shot at debugging later.