After 6.1amd64 -> 6.2amd64 upgrade namecoind malloc(): free(): error

I used namecoin on 6.1amd64 statically builded from source using boost
1.61 library. All works pretty fine before upgrade to 6.2amd64.

I have rebuilt the the same namecoin source with boost 1.61 lib statically.
After running it on OpenBSD6.2amd64 I see the error with malloc() and
free() listed below:

namecoind (4563) malloc():bogus pointer (double free?) 0xdfdfdfdfdfdfdfdf
namecoind (4563) free(): chunk is already free 0x1bc9981cae20

Is something changed in malloc() since than?
How to get work statically built namecoin on 6.2?

Thank you for answer in advance.

Denis