I put some data into storage.sync, but can it be shared?

Add-ons Development
#1

I put some data into storage.sync and can read it from the same device. On other device I have logged in with my firefox account, on both devices I have checked “Addons” flag in sync settings and then pressed sync button (this one) on both. After this I can read my data on the first device but on the second storage.sync is empty.
Both firefoxes are desktop versions. How should it be done?

And is it ok that reference said I can store up to 100KB but I managed to put and read almost 5MB? (still on the same device)

#2

Is the add-on signed or does it have an ID in the manifest? Did you test with a small data payload or did you try with 5Mb from the start?

#3

Addon is signed as unlisted on AMO, ID is set, and yes I tried to store just a single word

#4

Actually now data < 100 KB was synced well. Maybe service was confused last time after I tried overweight data and so couldn’t sync even few bytes for some period of time.