[Turmux][ffmpeg] encounter "can't open stat file" when use "-pass"

I installed ffmpeg in turmux, in my home directory, ran:

ffmpeg -y -i /sdcard/FFMPEG/in.mp4 -c:v libx264 -b:v 2600k -pass 2 -c:a copy /sdcard/FFMPEG/out3.mp4

the error bumps:

ratecontrol_init: can't open stats file

if I enter /sdcard/FFMEPG folder first, then run ffmpeg -y -i /sdcard/FFMPEG/in.mp4 -c:v libx264 -b:v 2600k -pass 2 -c:a copy /sdcard/FFMPEG/out3.mp4 the task will run successfully.

then I went back to turmux home directory, ran ffmpeg -y -i /sdcard/FFMPEG/in.mp4 -c:v libx264 -b:v 2600k -pass 2 -c:a copy /sdcard/FFMPEG/out3.mp4 , error still happens.

so I then added -strict -2 -passlogfile /tmp/mydummy and ran ran ffmpeg -y -i /sdcard/FFMPEG/in.mp4 -c:v libx264 -strict -2 -passlogfile /sdcard/FFMPEG/ -b:v 2600k -pass 2 -c:a copy /sdcard/FFMPEG/out3.mp4 , and same error still happens.

My question is, how to use ffmpeg "-pass" in termux successfully without especially entering the target folder?