My theory (totally from my own head/people's anecdotes rather than any research) is that it's behavioural, but the behaviour that tends to lead to more consolidated independent sleep earlier is correlated with bottle feeding.
Consider this: A baby wakes in the night.
If you're breastfeeding, the easiest thing to do is to feed them back to sleep. It's instant, it works, you don't have to think about it, you don't even have to be particularly awake (once you've got the hang of latching anyway), you are probably more likely to bring them into bed and you all go back to sleep. Baby likely falls asleep with boob in mouth. If they wake an hour later you just do the same thing again. Most co-sleeping breastfeeding mothers report that their sleep is not very disturbed by night feeds, especially in the in between phase (newborn is tricky because of wind, nappies and getting started with breastfeeding; toddlers tend to turn into windmills with a limb in each parent's eye)
If you're bottle feeding, you have to go and get the bottle, and to do that means getting out of bed (or waking up partner and sending them) so you probably initially try something like jiggling, shhhing, patting, rocking or offering a dummy. This is easier than getting a bottle. You probably do this even if you're not actively trying to stop night feeds yet because the baby is still too little.
If you do give up and get the bottle, you might have to go to another floor of the house, you almost definitely have to go to another room. You might have to wait for the kettle or the prep machine or the bottle warmer. You might have to perform thinking tasks like counting scoops or seconds. It's likely that it is at least a couple of minutes if not longer between you making the decision to get the bottle and the bottle being available to the baby. Even if you decide immediately to offer the bottle, the baby has to wait for a brief period first.
If the bottle is empty before the baby falls asleep, it is unlikely that parents will get a second bottle. They'll try other methods to soothe the baby - a dummy, rocking, patting, holding, or some babies are happy to be laid down now that they have a full tummy and just go off back to sleep (the legendary "drowsy but awake" 
)
If the baby wakes 45 minutes later, the parents are likely to think that hunger is not the cause of waking and try other soothing methods for longer before offering a bottle.
So the bottle fed baby is more used to falling asleep in different ways. They are not expecting to get fed immediately on waking up. Sometimes they will be able to be soothed to sleep without feeding at all (parents find it easier to soothe in other ways than feeding, vs breastfeeding mothers finding it easier to breastfeed vs other soothing methods, humans tend to default to the easier option) They may be more likely to sleep in a separate space where they can't smell milk and follow instinctual rooting behaviour.
Anecdotally, it seems to me that people who breastfeed but in a pattern more closely following typical bottle-feeding patterns - roughly sticking to a routine, trying not to feed all the way to sleep, ensuring to put baby in a separate sleeping space, trying other soothing methods before feeding - you tend to see that babies fed in that way follow the more typical bottle feeding sleep patterns.
Also, some babies are just unicorn sleepers / wakeful sleepers whatever you do and will do their own thing regardless of what you try, but I think there's probably a good majority in the middle that can be swayed by parental behaviour and this is why you tend to see a generalised difference between bottle fed and breastfed babies.
But I also think it's unhelpful to moralise sleep - more consolidated, independent sleep is not the only goal and I don't like seeing things as feeding to sleep or co-sleeping called "bad habits", personally I found that cosleeping and feeding on demand works absolutely brilliantly for me and it's my preferred method right up until the point that it stops getting us more sleep. I did refine it a bit over 3 babies and currently working on getting DS3 to spend more of the night in his own cot, a year or so earlier than I bothered with the other two and yes, it's clear that parental behaviour can absolutely influence the baby's waking pattern.