iparm[35] = 1 or 2 question

Dear Intel

I'm a user of MKL 2018 up1 parallel studio.

Usually I handle the large matrix(>50Mx50M) using schur complement.

'iparm[35] = 1' is the my general setting and it shows the schur complement matrix.

However, when I changed the setting 'iparm[35]' from 1 to 2, they shows the error message during factorization (phase=2)

Error code is -4. (not SPD)

Already, I checked iparam[29] and matrix->a[iparam[29]], but there are no zero pivot or wrong conditions for SPD.

I think, if the matrix is factorized with 'iparm[35] = 1', then 'iparm[35] = 2' should be also OK.

I ask your advice.

Thank you very much in advance!!!

Regards,
 Yong-hee