I think I need to see the Awesome Miner log file for this scenario. Can you send by mail?
I sure will. Just cleared the logs on both AM and AM Agent on my test miner and restarted with 5 algos selected. Once it acts up (switches to a less profitable algo), I'll uncheck all but Ethereum and start miner to get that false positive error message about the pool not being configured correctly.
To get insight why the profit switcher selects a specific algorithm, right click on the miner and select View Details and go to the Profit switching tab. Please note that these hashrates and profit estimates are based on what is defined in the Profit profile. They may not match the actual hashrate and profit. If they are not matching, please use the Benchmark feature or manually edit the profit profile to ensure they match, otherwise the profit switcher may select a less profitable pool.
Everything here looks good as far as I can tell when I first start out. Here's what it looks like atm and the listed hash rates are based on actual benchmarks I ran.

Also note that the pools in the Options dialog, Pools section, are by default not considered by the profit switcher. You need to create a Pool Group of those pools and then specify it as a "Custom pool" in the Options dialog, Profit switching section.
I understand, I'm not trying to use those pool definitions for the profit switcher, I'm only using the one defined here (if I understand correctly since I don't currently have any Pool Groups defined):

Ok it just happened again. Here's what I see under details:

As stated before, all my other miners (which only have Ethereum selected as available algo) continue to mine just fine against the NiceHash Ethereum pool.
When I click "Reset failed pools", it immediately switches back to Ethereum and all as well again.
I have zipped up the log files and will forward them to you shortly.
EDIT: Increasing the "Ignore pools with no accepted shares" from 8 minutes to 10 minutes (the max), seems to have resolved the issue. I suppose a rig with a single 1050Ti just doesn't hash ETH fash enough to produce a share in 8 minutes?