There are lines above words. This does not affect 1.17.11 so, I will be using 1.17.11 to show how it should look like.

This affect every single type of command as well

This was done in a world which was not exported from the beta. Both of these pics were obtained from a brand new world. This wording bug also affects 1.17.11 worlds which were exported into 1.17.30