NSD 4.2.0 intermittent segfaults @ libssl ?

I just bumped NSD

	nsd -v
		NSD version 4.2.0

on a linux64 VM.

On axfrs, I'm seeing segfaults in libssl

	Jun 11 08:53:24 ns03 nsd[12296]: axfr for example1.com. from 109.74.194.10
	Jun 11 08:53:24 ns03 kernel: [35762.840704] nsd[12296]: segfault at 560244acb618 ip 00007fefedb81406 sp 00007ffe6c552ac0 error 7 in libssl.so.1.1[7fefedb43000+86000]
	Jun 11 08:53:24 ns03 nsd[12246]: server 12296 died unexpectedly, restarting
	Jun 11 08:53:24 ns03 nsd[12225]: [2019-06-11 08:53:24.960] nsd[12246]: warning: server 12296 died unexpectedly, restarting
	Jun 11 08:53:25 ns03 nsd[12246]: process 12296 terminated with status 139
	Jun 11 08:53:25 ns03 nsd[12225]: [2019-06-11 08:53:25.030] nsd[12246]: warning: process 12296 terminated with status 139
	Jun 11 08:53:25 ns03 nsd[12297]: axfr for example2.com. from 207.192.70.10
	Jun 11 08:53:25 ns03 nsd[12225]: [2019-06-11 08:53:25.557] nsd[12297]: info: axfr for example2.com. from 207.192.70.10
	Jun 11 08:53:25 ns03 nsd[12225]: [2019-06-11 08:53:25.557] nsd[12297]: info: axfr for example3.com. from 207.192.70.10
	Jun 11 08:53:25 ns03 nsd[12297]: axfr for example3.com. from 207.192.70.10
	Jun 11 08:53:25 ns03 nsd[12297]: axfr for example4.com. from 207.192.70.10
	Jun 11 08:53:25 ns03 nsd[12225]: [2019-06-11 08:53:25.565] nsd[12297]: info: axfr for example4.com. from 207.192.70.10
	Jun 11 08:53:25 ns03 kernel: [35763.583172] nsd[12297]: segfault at 560244acb618 ip 00007fefedb81406 sp 00007ffe6c552ac0 error 7 in libssl.so.1.1[7fefedb43000+86000]

Note, *NOT* on every axfr; some seem to work.

Just starting to troubleshoot here ...

Any obvious issues that are already known that might cause this?