https://bugs.openldap.org/show_bug.cgi?id=10024
--- Comment #1 from Howard Chu hyc@openldap.org --- I can confirm that there's now a bug in env_open2 in mdb.master3, it's calling read_header with an uninit'd meta struct.
https://github.com/LMDB/lmdb/blob/mdb.master3/libraries/liblmdb/mdb.c#L5295
Will work on this soon.