The Deadly Beam currently cannot be used in certain situations, where teleport could not be used.
This mainly means tight spaces, such as the hammer room of NOTG.
The error message is: "Sorry, you can't teleport... Try moving away from blocks."
I am not sure, if this is considered a bug, but it is certainly not convinient for the ultimate ability of Riftwalker.
I wish, this interaction was handled!