I ran into this issue, looks like maybe a few other people did as well. https://github.com/jonmosco/kube-ps1/issues/28#issuecomment-359761463 A simple clarification seems helpful.
@@ -55,6 +55,8 @@ plugins=(
# After the "source Oh My Zsh" line
PROMPT=$PROMPT'$(kube_ps1) '
+# Or in double quotes, don't forget to escape
+PROMPT=$PROMPT"\$(kube_ps1) "
```
Note: The `PROMPT` example above was tested with the theme `robbyrussell`.