Thanks for the bug report.  This is a case of something that used to work fine but was affected by an incidental change elsewhere.   

To support the use case for deterministic sequences of values starting from a known point, the docs promise, "If a new seeding method is added, then a backward compatible seeder will be offered. The generator’s random() method will continue to produce the same sequence when the compatible seeder is given the same seed." (See https://docs.python.org/3/library/random.html#notes-on-reproducibility )

The resolution is to have the random module (line 327 in Modules/_randommodule.c) use a new _PyObject_Hash() function that deterministically matches what the old PyObject_Hash() function used to do.

Marking this as "needs patch" and saving it for Nofar Schnider to work on (she's an aspiring core dev).