Default [4.3]google accounts don't sync automatically, no error.

device details:
Note 2 N7100, hurricane V6(near-stock 4.3)
xposed framework with several modules.
problem occurs over 3G, HSDPA, and Wi-Fi.

exact problem:
both my gmail accounts refuse to sync by themselves.
I can leave my phone alone for 8 hours, and under "accounts" it will still show the last time I checked my mail as the last sync time.
I have to manually sync or check mail to receive anything.

actions preceding the problem:
2 days ago I was forced to factory reset my phone because I messed up some permissions(I copied profile data from firefox stable to nightly and changed the owner, somehow this changed permissions outside the nightly data folder, which should be impossible unless they use weird symlinks)
after the rest I had to wipe internal storage, somehow the /emulated/0 folder was read-only preventing apps from using storage but I fixed this by wiping internal storage using its real location(/data/media)
after this I realised I didn't receive mails, and sync times didn't update.

attempts to fix the problem:
I wiped gmail data, no change.
I removed and re-added my accounts, this only triggered a 1 time sync.
I rebooted several times, including once between removing and re-adding accounts, no change.
I checked system wide sync setting, this was enabled.
turning sync off and on will trigger a 1 time sync for everything, currently I use this as an emergency fix in tasker(every 15 minutes between 07:00 and 23:00)
I checked settings for the individual accounts: calendar, apps, gmail, and contacts sync are enabled.
I checked gmail again, no message stating sync is disabled or malfunctioning.
I have also left my phone alone for a few hours on mobile data and on Wi-Fi, my phone didn't receive my test-mails until I manually checked.

does anyone have any idea what could prevent sync without actually telling android it can't sync?