Words with pronunciations more complex than spelling

The word mischievous is sometimes pronounced with a long e sound between the v and the last vowel (mis-chee-vee-us), although this is controversial.

Is there a name for this type of word, where the pronunciation is made more complex than the spelling indicates?

The name for the type of error is misconstruction:

misconstruction 2. Grammar A faulty construction, especially of a sentence or clause.

Although the definition refers specifically to sentences or clauses, it can be used for single words as well.

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From NOAD, for those who think "mischievious" is a variant:

usage: Mischievous is a three-syllable word. Take care not to use this incorrect four-syllable pronunciation: |misˈCHēvēəs|.