In standard Arabic, and for most languages using the Arabic script, when U+0650  ARABIC KASRA follows U+0651  ARABIC SHADDA the kasra is moved to just below the shadda (behavior for U+064D  ARABIC KASRATAN should be consistent with the behavior for U+0650  ARABIC KASRA). This behavior is what is seen on the left below. However, some languages require the kasra to remain below the consonant as is seen on the right below. Sindhi and Urdu are two well known languages where the behavior demonstrated on the right is expected.