I haven’t seen the druid behave like that. Evil minions sometimes disguise as outcasts, so if the druid is saying there are no outcasts, the outcast might be a minion in disguise. (Demons have a special rule that says they can’t disguise as outcasts or share disguises with a truthful/corrupt but good villager - they are one of a kind or sharing a disguise with the drunk or another evil.)
The only time I’ve seen a truthful druid say there are no outcasts when there is one is when I point the druid at a wretch … but that’s supposed to happen because the wretch looks like an evil minion to all the other characters, not a wretch. If a druid says they see a wretch, they are lying.
Edit: This assumes you are playing the itch web version. If you are talking abut steam, there are new cards and bugs that may cause too many outcasts to appear.