Map Rolling Regex Matching Bug

I was rolling T16 Mirage Maps with the following regex, using chaos followed by exalt slams: "y: r" "!unid" "!tanc|ery r|f ph|er,|ur$|efe|wni|on,|tab|wb|non|m el|reg|sks|rch$"

The bug I found is that there are some maps which at first don't appear to match the regex, but when you take them out of the tab and put them back in, suddenly they match again. In practice I've seen this happen to about 50% of the maps I roll. That means that if you're unaware of this bug, you're probably wasting a lot of currency rolling maps.