Experiencing the same issue. When applying multiple filters in Magic ETL, it returns 0 results. Even though I see the raw data and it's clearly there, however, can't use filters to get the sample of the data.
I work in Domo Support, and can provide some help here.
Very often, with this type of issue, it'll turn out that something weird is happening with whitespace. Examples I run into a lot are:
I advise you review your data to see if any of these issues exist, along with simple spelling errors in the data that aren't in your filter value.
If you can't find the cause of the problem, please go to support.domo.com and submit a support ticket. Please indicate the dataflow you're working with, which filter tile/s you're looking at, and which value/s in your data you expect to make it through the filter tile that are not making it through.
Solved (for me):
Filtering using 'does not contain' on a simple text string. I got it to work for a single filter on my first try, but as I tried to add other filters it stopped working. The Run Preview process just refused to do anything once it got to the Filter Row step.
Then I stumbled upon what I think was the problem for me, and probably others. After you type in your rule, there is a big button labeled "Add Filter Rule". I should be forgiven for thinking that is what you are supposed to hit to complete the process of adding the rule just above. But what it seems to do is actually open up a new rule dialogue box, and if that dialogue box remains open, the process fails. Once I closed that empty dialogue box by hitting the large "X" to the right, everything processed fine.
I have replicated this problem, and added several more rules and it all works great.