Even if you often try to make that person feel understood and empowered to express their views, everyone’s needs are different. For example, if they tend to feel inadequate or are self-conscious about their achievements/intelligence/etc., you may need to go the extra mile here.
Try to identify all the positive and negative interactions with them (i.e., those in which they get the impression that they are right versus those in which they don’t) and make sure that positive ones greatly outnumber negative ones. If you need, you can try to acknowledge more situations wherein their contribution to a conversation deserves praise, or even simply not point out their mistakes if the question at hand is not critical for you (easiest imo).
This is amazing, I think it could even nicely fit a use case in a project of mine. Thanks!