Or MDEV-13935?
Assigning to marko to take a look.

The latest is #18904:

commit 025aee64e0382e728bedc9e71da441be745d7650 (origin/bb-10.2-compatibility)
Author: Alexander Barkov
Date: Fri Feb 2 22:38:35 2018 +0400

Temporarily compile release builds with -O0 and -DTRASH_FREED_MEMORY

commit 4025cfaec038594bfc97bea48aa2cfe139930cc2
Author: Alexander Barkov
Date: Wed Feb 28 23:05:57 2018 +0400

MDEV-15416 Crash when reading I_S.PARAMETERS

There is also #18409:

commit 14d1af00586d05f89381ea28c9890c3dd501dbfc
Author: Alexander Barkov <bar@mariadb.org>
Date: Fri Aug 18 23:36:42 2017 +0400

MDEV-11952 Oracle-style packages: stage#5
…
commit e300f0c9612559bc5c80830f9b98e46bb010d7d1
Author: Monty <monty@mariadb.org>
Date: Tue Jan 30 21:32:19 2018 +0200

MDEV-15133 array bound (bulk) parameters of NULL propagate on next rows

null_value was not properly reset when setting parameter value

(The parent commit in each of these exists in the bb-10.2-ext branch.)

The newer build (18904) included a merge of MariaDB 10.2 as of February 22 (February 22). MDEV-13935 was fixed March 13.

I think it is very plausible that the hangs were fixed by MDEV-13935.

The older build (18409) included a merge of MariaDB 10.2 as of January 26. It is also missing some FOREIGN KEY fixes in 10.2.13 (MDEV-15199,MDEV-14222), but these fixes are already present in build 18904.

In my opinion, this should be fixed by merging 10.2 to bb-10.2-compatibility. If that is out of the question, then by cherry-picking the MDEV-13935 commits.

Marko, I reminded support team that upgrade is needed. Can you please further work with support on this issue? Thanks.

The 2 MDEV-13935 commits are the 2 commits before the top commit of bb-10.2-compatibility build 20620. Did upgrading to that build (or later) address the problem?