splitting?

Twice now unintentionally ( when trying to move some text) I have ended up with another doc being made - Eg I had a document ‘Child’ and then I had 2 docs: ‘Child’ and ‘Child1’. It was a bit freaky at first because I thought I had lost most of my doc but turns out the content was separated into the 2 docs. The only thing missing was the paragraph I was trying to move. Clearly I am accidentally hitting a key or something and operating some function but I am not sure how I am doing it. Or how to fix it. Neither doc had the possibility to undo so I could not retrieve the missing paragraph.
Advice needed thanks

Could you have hit Cmd K in error, or thought you were doing something else? That’s the keyboard command for Documents > Split > At Selection (although I don’t know why you lost a paragraph in the process). Just below in the Documents menu may be the remedy, however: Documents > Merge, or select the two documents and Shift-Cmd M.

This has been happening to me lately. Apparently in PC it’s caused by short cut Ctrl+Shift+K.
I can guarantee that I am not that deft or clumsy to hit three keys at once without looking down. No something else freaky is happening due to latent short cuts. The salutary point of these mishaps is I never lost a paragraph. The two documents in binder ended up combined via cut and paste. I don’t usually notice the split for several minutes while I am involved typing!
It bugs me that the bugs make me work longer!!

There’s also a Documents → Merge command. No need to use copy and paste to reglue an inadvertent split.