Restricted consonant gradation

Hi list

As you may have read, my conlang Vallian has consonant gradation, whereby (
e.g.) rr -> r (in one dialect) in closed syllables.

However, my language is intended to be polysynthetic/non-configurational, so
given unrestricted consonant gradation, the following could happen:

kerel "bird", nom. sing. -> "kerrel-le", nom. dual -> "kerre-la-s" nom.
sing. inflected in agreement with feminine noun in the ergative.

Is having CG in noun/adjective/verb stems, but not for suffixes, credible?

TIA

Jeff