Postgresql 12 Beta2 Crashes for any Insert/Update

i have a working database in PG 12 Beta 1. today i upgraded it to Beta 2.
everything goes fine and server is up and running. but trying to
INSERT/UPDATE anything, server crashes:

=# select id from user where id=0;
id ----
0(1 row)=# UPDATE user SET is_deleted = true WHERE id = 0;
psql: server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.

and the server log has nothing more:

2019-06-27 12:49:07.348 [16336] LOG: server process (PID 17680) was
terminated by signal 11: Segmentation fault2019-06-27 12:49:07.348
[16336] DETAIL: Failed process was running: UPDATE user SET
is_deleted = true WHERE id = 0;2019-06-27 12:49:07.348 [16336] LOG:
terminating any other active server processes2019-06-27 12:49:07.348
[16436] WARNING: terminating connection because of crash of another
server process2019-06-27 12:49:07.348 [16436] DETAIL: The postmaster
has commanded this server process to roll back the current transaction
and exit, because another server process exited abnormally and
possibly corrupted shared memory.2019-06-27 12:49:07.348 [16436]
HINT: In a moment you should be able to reconnect to the database and
repeat your command.2019-06-27 12:49:07.350 [17787] postgres(at)db_01
FATAL: the database system is in recovery mode2019-06-27 12:49:07.363
[16336] LOG: all server processes terminated;
reinitializing2019-06-27 12:49:07.821 [17788] LOG: database system
was interrupted; last known up at 2019-06-27 12:39:53 2019-06-27
12:49:07.858 [17788] LOG: database system was not properly shut
down; automatic recovery in progress2019-06-27 12:49:07.868 [17788]
LOG: redo starts at 4B2/5A000AF82019-06-27 12:49:07.868 [17788] LOG:
invalid record length at 4B2/5A000B30: wanted 24, got 02019-06-27
12:49:07.868 [17788] LOG: redo done at 4B2/5A000AF82019-06-27
12:49:08.063 [16336] LOG: database system is ready to accept
connections