I am writing a lot of CJK words Western text.
When I type Western text, then change to CJK (Kotoeri or so) text input, start typing the cursor jumps several characters back to the left, the text I type and the Western text already typed cover each other. When I hit enter and the final text version appears, the text looks OK, and there are no problems with the output.
When I wright pure Japanese, no such problems occur.
But when I type an accent in a Western text, there is as similar behavior: e.g. “`” which shows code. These characters have a similar “intermediate state” before they are set – like writing in CJK. The jump to the left as well before I hit enter and everything looks good.