I'm hoping it's just residual gut-healing stuff, not a long-term issue, and something that evens out over the next few days.
BUT, if it doesn't improve you may want to talk with the Ped GI (or doctor) about thickening feeds - I don't remember the name of it
but there's a thickener which does work on breastmilk (it's available at most hospital pharmacies, it's used on patients after strokes etc. to thicken their feeds) -- I suspect that it has corn in it though. It would work on Neocate as well, and would (as long as it's corn-free) also probably be better than trying to 'thicken' feeds with rice.
I really dislike the thickened feed approach. Especially with a breastfed baby, I feel that aspirated breastmilk is preferable to aspirated breastmilk-thickened-with-something. BUT, maybe it's something that would help with the silent reflux?
Dd1 continued to reflux once her allergies were under control; the two were separate issues. Neocate didn't seem to increase her reflux pain/issues, but she was on max dosage of Zantac the whole time -- and, at the time, Reglan was still commonly used and she was on Reglan too.
I wouldn't do Reglan again knowing what I do now, but at the time, it did help us.
Fortunately we had no adverse side effects, then or now.
Here's really hoping that it rights itself on its own without having to worry about that sort of thing though.