Browsing further through St. Mary of the Assumption baptism register for the same few years may identify other examples which may add weight to my theory, or not. I only glanced at a couple of months. Browsing registers sometimes provides clues to possible explanations that a narrowly focused search wouldn't. The babies I mentioned in my own village were all of single mothers in a rural parish.
Burnley workhouse may have had its own chapel. I imagined the priest visiting regularly like a hospital chaplain and carrying out whatever duties were necessary. I hope he washed his hands between the infirmary and the nursery. His visits may have taken place during the week; potential godparents would have been at work. Anyway, mothers may not have had prior notice of visit. There may have been Sunday mass in the workhouse chapel, followed by baptisms. You can calculate day of the week Agnes was baptized.
There was a similar query last week with the title "Side note on baptism". I commented on it. I can't find it today.
Are you a member of a library in Britain? If so, you may be able to access newspaper archives, if your library has a sub. If not, I can look up the articles but I could only give you a summary. I'm a computer novice. I'm also still learning about using online newspaper archives.