I am also having the same issue. I am using Syncthing and Joplin on Android. I really like Joplin so far, but this bug makes it hard to be completely confident that my data will stay intact.
Edit: I have searched Syncthing’s issues and forum and no one seems to have mentioned this over there. I would try create a post, but not sure I can gather enough info to make a meaningful bug report.
Edit2: After thinking about what @laurent said about leaving previous content at the end, I tried making a simple note in Joplin and then deleting a line to make the note shorter. This immediately triggered the problem.
Test syncthing and joplin
This is a note to test what is corrupting my notes.
1
id: e393a5186da742899147eb516d0c3ddd
parent_id: 132f72eb544549378dc8f7222e47fef8
created_time: 2019-12-05T13:46:36.923Z
updated_time: 2019-12-05T13:47:30.865Z
is_conflict: 0
latitude: 0.00000000
longitude: 0.00000000
altitude: 0.0000
author:
source_url:
is_todo: 0
todo_due: 0
todo_completed: 0
source: joplin
source_application: net.cozic.joplin-mobile
application_data:
order: 0
user_created_time: 2019-12-05T13:46:36.923Z
user_updated_time: 2019-12-05T13:47:30.865Z
encryption_cipher_text:
encryption_applied: 0
markup_language: 1
type_: 1: 1