This happens when you write in a command block after putting §2 or another color, meaning that when you put letters in front of §color, what is behind § is removed. This happened to me when I updated to ios17 and then downloaded version 1.20. 30 and it happens in the command blocks but if I put §2 at the beginning it is not deleted and you put it later it deletes what is behind § but not what is in front of §2 or another color and so on
(This did not happen in the iOS 16 version and just in the previous version of Minecraft)
The posters too and on the search ñ does the same