Cold Blood still is having the error when being used in a macro while in Sub spec.
This can be recreated by logging into the game as Sub with cold blood talented. Switching specs to Assassination with the Fatebound Hero talents selected and the talent node Inevitability taken (454434). Then switching specs back to Sub.
Relogging fixes this issue. If you are ever in a situation where you are wanting to switch specs in an instanced location that you aren’t able to relog like the irratic state of tuning in delves; relogging isn’t an option.
This seems like there is some sort of caching taking place that isn’t being cleared whenever you switch specs.
Slight edit: you can confirm that the game does know on the client side that you know the ability by having the line ‘/cast [known:382245] Cold Blood;’ in your macro and it still fires off the event.