Any suggestions to prevent Replit from changing design elements that I don't instruct it to?

Today's my first day in Replit, so I'm getting a feel for the chat Agent builder to build a client note-storage system.

It's providing me with solid designs, but it keeps modifying elements that I don't want it to change, even after I explicitly request that only the specific changes I want are to be sent back.

If my whole application is represented by A through Z and I say, "Everything is great except X Y and Z...make these changes", it sends back a version with A through F modified (and not even X Y Z correct some of the time).

Also, once in a while it throws a design back that's completely corrupted and buggy.

Any suggestions for how to prevent these two issues? Thanks in advance.