I second that.
I use _the same_ XnviewMP 1.9.2 as an appimage with portable home and config folders on identical Arch(Manjaro) instances. The only difference is filesystem Linux is installed on - ext4 and btrfs.
On ext4 deleting sends the files to Trash folder. On btrfs, they do not go to Wastebin even if they are deleted on an NTFS partition.
I'm having the same problem on Debian. Except, when I delete the file on the system drive, it sends it to the recycle bin, but on an attached USB hard drive, it doesn't. Both are using the BTRFS file system.