Segmentation fault (core dumped) using dynamic format

As a follow-up for #3417. Just finished full test of the fix. No more stack smashing errors but a segfault when the session is almost completed:

..
Almost done: Processing the remaining buffered candidate passwords, if any
1: Warning: Only 20 candidates buffered for the current salt, minimum 48
needed for performance.
1: Warning: Only 17 candidates buffered for the current salt, minimum 48
needed for performance.
1: Warning: Only 11 candidates buffered for the current salt, minimum 48
needed for performance.
1: Warning: Only 26 candidates buffered for the current salt, minimum 48
needed for performance.
1: Warning: Only 32 candidates buffered for the current salt, minimum 48
needed for performance.
1: Warning: Only 30 candidates buffered for the current salt, minimum 48
needed for performance.
1: Warning: Only 39 candidates buffered for the current salt, minimum 48
needed for performance.
1: Warning: Only 37 candidates buffered for the current salt, minimum 48
needed for performance.
1: Warning: Only 46 candidates buffered for the current salt, minimum 48
needed for performance.
1: Warning: Only 47 candidates buffered for the current salt, minimum 48
needed for performance.
1: Further messages of this type will be suppressed.
To see less of these warnings in the future, enable 'RelaxKPCWarningCheck'
in john.conf
Segmentation fault (core dumped)

Any advice about how to supply you with useful debug info? Thank you.