Ok too much information in this thread which I find hard to follow, it would have been easier if you put all the info (summarised version of your issue) in one post, so tell me if this is correct:

You have a few Antminers of different models all running stock firmware and pointed to slush pool aka Braiins Pool, some of these miners are working fine right now, and some are not.

If that is correct, then you need to point the non-working miners to a different mining pool to ensure this is isn't a pool related issue, don't just take their words for it, if their logs are not showing any errors and they can't reproduce the error -- they will always tell you (nothing is wrong on our side), this is true for ALL other pools and services, so assuming that there is nothing wrong with their pool is a naive mistake, they could have had an update to their pool software which somehow screwed things up.

Different miners use different firmware, and thus it's perfectly normal for miner "A" to work fine on pool "Y" while miner "B" does not, so long story short, point them to a different pool and report your results.