I tried the original Japanese and my version again and they both seem to run fine, there are some micro stutters in the larger maps in both versions, but there's no lag or stuttering when indoors or on a smaller map. Perhaps something got messed up when uploading? I'll download them and test them, but if it's not just simply having to re-upload the files, then I'm not sure what is causing the lag for those that have it. I play on PC, are other people on PC having the lag issue as well or is it just phones?
I tried your save file on my game and the Japanese v1.18 versions and it runs fine. Micro stutters occur in both versions for me in the larger maps, but the game still runs smoothly. Sorry, I'm not sure what might be the problem.