How many old houses I've disected for one reason or another either to do a repair or some kind of alteration only to find the beams butchered by previous trades...."especially" plumbers.
In my own house...a circa:1680 you should only have seen the butchering that was done to this place. And it's been here way over 300 years.
Someone added three windows to the eave side of the house and joined together (no studs between them)....get this...never added a header over them. Thats about 15' span!! I took the windows out when
I added on. the entire 12x12 above where the header should have been was cracked clean through and the entire corner of the house was sunk down until it was leaning over. I had to add 4 18" lam beams I think it was after I jacked the corner of the house up. It WOULD HAVE come down on someone eventually!!.........So never say never...RIGHT?!
Always err on the paronoid side...lol.