Sometimes rclone take very big amount of memory

i have rclone with crypt mounted on amazon cloud drive and google drive, those folders are as remote points in nextcloud.
Sometimes, on acd, rclone without any reason takes 1GB of mem, why?
i have it mounted this way:
rclone --config=/root/.config/rclone/rclone.conf mount -v --buffer-size 8M --acd-templink-threshold 0 --default-permissions --no-modtime --dir-cache-time 30m0s amazencrypted: /acd --allow-other --gid=33 --uid=33 --umask=0000 &

By default is taking 16MB per open file on mount, what you could try is set --buffer-size 0 and then check.

p.s. Since files need to be decrypted in memory that will also take a toll on memory.