Impostor syndrome
People might not internalize their achievements, causing them to feel like they did not earn those. This makes them feel a constant fear of being exposed as a "fraud". This is very common and I have no idea on how to avoid it (either for myself or for others).
[#stanier-effective-manager] suggests in its 10th chapter that pairing different level people might show them how far they've come. The author also suggests reinforcing good achievements for these people.
202105051358 Coaching and 202105051235 Mentoring might also be good tools to deal with that.
Source: https://en.wikipedia.org/wiki/Impostor_syndrome
[#stanier-effective-manager]: Stanier, Dr. James. Become an Effective Software Engineering Manager. 1st ed. S.l.: Pragmatic Bookshelf, 2020.