I got the suggestion from this post: https://dietpi.com/forum/t/transmission-cant-remote-access-when-a-torrent-is-downloading/4227/5
Apparently, your solution to another issue also solves this problem with Transmission.
As requested below.
NAME FSTYPE LABEL SIZE RO TYPE MOUNTPOINT PARTUUID UUID
sda 461.3G 0 disk
└─sda1 exfat torrents 461.3G 0 part /mnt/torrents eea31415-8459-46d6-b70b-4789a4f9d925 BE1F-09DF
sdb 116.1G 0 disk
└─sdb1 ext4 116.1G 0 part /mnt/cops bcd52a68-87c1-4b81-929f-7345b26281ef 561325f0-6181-41ad-a79c-1acef5a4c729
mmcblk1 7.5G 0 disk
└─mmcblk1p1 ext4 7.5G 0 part / fbb3d018-01 92b2ac71-76f3-4e7f-a35f-1fbe34221b88
total 260
drwxrwxr-x 3 root dietpi 131072 Jan 11 12:05 .
drwxr-xr-x 8 root root 4096 Jan 8 11:58 …
drwxrwxr-x 2 root dietpi 131072 Jan 11 12:00 transmission