This is very frustrating. Most changes are syncing when I log out of the app and then back in. However, for some reason, there is a very stubborn correction that doesn’t update on the ipad or the iphone.
‘I read a Korean book.’ this one hasn’t updated despite being fixed a long time ago. I have since logged out and logged back in many times.
I’d suggest you try and clear the cache in your device’s app-settings, then uninstall, reboot and install again. I was able to work around such issues in the past when logging off and back on didn’t work - might be worth a try.
As you can see from my link this phantom entries bug is more than four years old. By which we can assume that Memrise does not care too much about bugs in user created courses. At the moment you can correct entries in your courses either manually, but only if they are visible in search field, or using this script. I wouldn’t expect it to be fixed in the foreseeable future.