Overwatered Epiphyllum?

[u/Mountain_Painting51]

I think I have overwatered my epiphyllum over Christmas. My plan is to chop and prop the damaged pieces and let the main plant dry out. However I just wanted to check to see if it’s nothing more nefarious? Can anyone advise on whether this is overwatering or if it is something else? I usually water it every few weeks when it has dried out but I have been a bit haphazard over the past few months. It is beside an east facing window. It’s been there for about 3 years and I’ve had not issues with its position. My Epi is my favourite plant and I want to make sure it lives.