Hopefully there is a configuration cure to avoid a bug report.

Any file that is opened in kate or kwrite resulting in the infamous 
warning dialog that the file is binary and editing will result in a 
corrupt file, renders both text editors into a non-editing mode.

For example, create a diff file using "diff -urNa" where there are 
file additions or removals in the target directory. Open the diff 
file in kate or kwrite. The infamous warning dialog appears and 
editing thereafter is impossible. Also disabled is searching and 
seatch-and-replace.

Bug or configuration problem?

Darrell