Hello vlc. No, I wasn't talking about anyone except myself. Glad to hear your daughter is doing well.
I can't reference the most direct description of the potential problems with catchup growth as I saw it in a book in a local boookshop when DD1 was less than a year, and she's nearly 9 now, so I can't remember the title.
Basically it said that infants who don't get enough nutrition when they are developing may not grow as fast, but they will catch up later. The problem was that for some reason the growth they did later wasn't quite as good.
Basically I just used this as another stick to beat myself with, especially as she was above the 50th centile at birth, and then after what I perceived as the initial setback, she was the smallest child of her age group any time we went out - I used to compare her mentally measure her height against everyone we met!!
I looked it up a while ago after seeing someone post about a very slow gaining baby like mine was. There are no definite studies that I saw that relate to breastfeeding, slow weight gain and later problems in life. Good news! There are studies which seem to think that retarded growth in the womb followed up by catchup growth can cause problems in later life like heart disease etc. Possible theories are that when nourishment is short the growing foetus 'prioritises' some development over others.
There was a study about children on an island where maternal nutrition was poor, and I think some infants didn't have enough food, which led to stunted growth or catch up growth, which again, wasn't such a great thing. I posted some links which I will try to find again now, but TBH I think it would be scaremongering, as it isn't a clearcut issue like some of the bf stats - really it's just me flagging up some slightly unnerving results, but really there's to enough to base any judgements on. The thing that I do find very reassuring is the thought that I'm sure the formula manufacturors will be aware of most feeding research issues, and I would have thought would have jumped on this one if it had much scientific evidence behind it.
To conclude my epic - it was something that worried me - a lot - for quite a long time, but I really don't think there's enough evidence for you to really be concerned yet.