When the CPython interpreter crashes - recent history entries are lost. An easy reproducer (on any Linux):
$ ulimit -v $((1024*256))
$ pip install -q gmpy2
$ python # started with empty history
Python 3.14.0a2+ (heads/main:e2713409cf, Dec 2 2024, 07:50:36) [GCC 12.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from gmpy2 import mpz
>>> mpz(2222222222222211111111122222222222222)**33322222
GNU MP: Cannot allocate memory (size=503998640)
Aborted
$ python # history is empty, again :(
...
That "works" both in the old repl and in the new repl. Sometimes you even can't recover all session from the terminal screen.
IMO, if it's a feature - it's a misfeature. I would expect, that all entered input will be preserved in the history. Or such behavior can be optionally turned on. BTW, this feature "doesn't work" in the IPython shell.