That's the one im using in all my miners, tried smiths firmware too. nicehash firmware too.
I have the exact same "problem" i decided to just ignore it as overall its 2-3ghs loss;
I posted about this in several places and got a few replies but nothing helpful. I can sum it up to people posting the same 101 troubleshooting suggestions and a handful of others saying they have the same problem.
It still happen once or twice a day. Its the top blade if you look at it in the webserver in miner status.
It look like a sharp dip in the pool's graph everytime;
https://i.imgur.com/xWe4wYX.png?1
Typically only last 2-3 minutes.
Edit: My S5 is batch 7 (used from bitmain) on the latest PCB.
Finally.. i realized a lot of people has this "problem" and they don't know!
last week i was helping someone on facebook setting up his cryptoglance.. and i saw one of his miner hashing half of it.. and i said like "hey look,, that's the problem i told you about, it's happening in one of your miners" and he was like.. "shit, i have never seen that before"
im pretty sure it's a common problem. but people are not all day looking at their miners, they just care about the average hashrate