I created a note on a task. Today, the task is there but the note is gone. In the interim I did rename the name of the task.
Did you create this note on the web version, or was it on a mobile device? If you check on another browser, another device, is the note still not there?
I created it on the web. I just now check my android tablet. I saw the missing note for 2 seconds -- then the sync kicked in and wiped it out.
No critical information however disconcerting that notes can disappear so easily. I also think that the way notes are created and edited is not user friendly.
I actually got the data from the backup ZIP files, nice feature.
I got lucky this time, however it would be nice to be able to schedule those backups more often than once per day.
Data can not just be lost with Todoist, as there are always backups and it's rare for things to just disappear. If you had not already grabbed the backup, I would have suggested clearing the cache for your browser to see if it would have resolved it.
Let me know if it happens again.