Update models.py to fix num_layers issue for scan_layer=False in Deep…

[deval281shah]

…Seek

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[RissyRan]

Thank you for the fix! Just a minor comment!

[RissyRan]

Nit: To be aligned with another branch, let's rename the index_j to lyr?

[RissyRan]

Also, you may want to filled in Description of the PR, otherwise, the unit test of checklist will fail before the merge :)