Marshmallow Time Drift bug I was planning to flash a custom Marshmallow ROM on my Samsung Note 2 and use it for some tests in which keeping accurate time (error of a minute either way is fine, not more). This report This Android 6.0 bug might make you late for your next appointment makes me reconsider. It says


  The drift is quite small and can't really be noticed under direct observation, but user comments on the Google issue have suggested that a delay of up to 15 minutes can be accumulated over a period of 12 hours – just enough to miss that all important meeting or be late for an exam.


Temporary fixes as suggested in the link (below) do not suit me, since the phone would be unattended during testing I plan


  Users have also figured out a couple of temporary fixes. One is to simply restart your headset, forcing it to sync the time with the network, while another instructs to manually switch over form 4G to 3G


I have not found any reports of this on the ROM developer site or here but Clock sync/clock running slow issue log reports this

My question: Has anyone observed it and how bad is it? (Even if not measured)
Android 6.0.1 apparently fixes the issue. I'm running it on my Nexus, so I can't say about custom ROMs, but it should be fixed in 6.0.1 based ROMs.

The bug was detected by me in 6.0 first because my alarm rang 21 minutes late. It was about a week after I bought the phone. A reboot fixed the time, and since I've upgraded to 6.0.1, I haven't seen an issue with time.