Glad to see I'm not the only one utterly annoyed by the bench 
So this has been specifically tested? They all behave exactly the same?
Now on the other hand, gallows are a bit like capitals and they always go near the front. And another set of double glyphs I see are vowels with a flourish (EVA a - y is the most common and certain one), which are very end-loving. If these characters are mostly claiming those specific places, it will also have as a result that the "core" glyphs, being the single ones and the bench ligature, get a bit less freedom of movement and appear to behave more similarly to each other. Does that make sense?
So this has been specifically tested? They all behave exactly the same?
Now on the other hand, gallows are a bit like capitals and they always go near the front. And another set of double glyphs I see are vowels with a flourish (EVA a - y is the most common and certain one), which are very end-loving. If these characters are mostly claiming those specific places, it will also have as a result that the "core" glyphs, being the single ones and the bench ligature, get a bit less freedom of movement and appear to behave more similarly to each other. Does that make sense?