A full update gives me a number of warnings about dependency cycles. Can this be safely ignored, or is some special handling required ?
You did not tell us, what are the exact messages you are receiving and what packages are in the cycle. So it’s impossible to tell.
Since pacman does not warn about cycles, I assume that are misreported warnings about one of the packages in a cycle being installed before another. Those are usually not an issue. But we would need to know, what the messages are and which packages they refer to.