Yes.
The most famous one prior to the Rubymar attack that cut off AAE-1,
EIG and SEACOM, was this incident in the Med:
https://www.bbc.co.uk/news/world-middle-east-21963100
That was 11 years ago.
I had (admittedly at a braai) a conversation with a marine professional that feels it would be hard for vessels involved with sabotage to not be flagged as suspicious activity and get away with it but we do live in the James bond era so…
Locating subsea cables at depth is not like taking the dog for a
walk. It takes expertise, equipment, money, bespoke vessels, time
and the risk of death of bad weather to do that.
So not entirely impossible, but not a cake-walk either.
Mark.