Beginning in version 2.2.0, there is a "catch-up mechanic" to allow folks who've somehow lost one or more Seditious Flyers to still collect enough Rebellious Spirits to complete the quest. Simply feed any normal hungry imp whatever food it's asking for and, so long as this quest is active, it will drop a Rebellious Spirit instead of the normal reward. (This is also the case in versions prior to 2.2.0; however, it doesn't help because in those versions no normal hungry imps spawn while this particular quest is active.)
- Note: Rebellious Spirits have no use outside of being the items you turn in for this particular quest, so there isn't a good reason to acquire more than the exact amount you need to complete this quest. In fact, you probably don't want to do this—it would just take up valuable inventory space.