For Church of England similar era I have come across cases where there was a rough notebook and the official parish register as there was a miscopy between the rough to full for one of the children of my direct male line ancestor in Warwickshire and both are imaged online + there have the civil birth indices and 1841/51 census to refer to. On the day the entries were scribbled down, every so often, perhaps once a month, the minister or the churchwarden copied those into the parish register. So if a priest did similar on a scrap of paper then dropped/lost/lit the fire with it inadvertently all the names would essentially have been lost. He certainly wasn't baptising with the register perched on the font and counting whether he had been given 3s or 2s/6d. It looks to me as the entries for 1845 July 9,15 & 16 were written using the same quill and ink. Also there were two churches and only one 'parish' register for both.
1844 & 1845 there was a change of curates Fr Michael Monahan/ Fr William Fortescue/ Fr O’Callaghan.
1846 Parish Priest Fr Eugene Crolly took over from Fr James O’Neill
https://www.drumcreeparish.com/content/view/771/322/Father O’Neill to Fr Fortescue: William, those baptisms in St John's last week, do you have the details?
2 or3 different R.C. churches in Drumcree Parish not to mention that in some cases records are deemed to be in Armagh and Lurgan and a bit of Antrim to boot? As on Irish Genealogy site.
Mixing things here. Lurgan Poor Law District/Registration District comprised of parts of 3 counties and multiple civil/church of Ireland and R.C parishes. Drumcree R.C parish comprises today and comprised 1845 of 2 churches St. John the Baptist and St. Patrick's.
https://www.drumcreeparish.com/content/view/82/319/ with the original St John's, Selshion (which was in the graveyard adjacent to the current St John's) now in the Ulster Folk Museum
https://www.ulsterfolkmuseum.org/stories/catholic-churchUse the stacked squares to change to Griffiths map
https://www.genuki.org.uk/big/IRL/ARM/Portadown/PortadownStJohnDrumcree R.C parish is all in Co Armagh this coloured map may be easier to see if full screen it.
https://www.johngrenham.com/records/rc_church.php?parish=Drumcree&churchid=213John Grenham drew the boundaries shown on the NLI site map.
https://www.johngrenham.com/blog/2024/01/03/catholic-parish-map-confession/