Hey, I’m using the following macro (just an example, got the problem with all castsequence macros):
#showtooltip
/castsequence reset=40 Reaper’s Mark, Horn of Winter
After the first press, the tooltip always switches to Horn of Winter, but sometimes the spell just doesn’t cast after the second press. Relogging (logout+login, not /reload) ALWAYS fixes that problem.
Generally this should work, I am using a similar one for blood, and it works fine for me (although its not optimal, low number of keybinds forced me to).
From your info, I do not really understand the problem, but it should generally work. Only problem that was similar, was on my shaman, that similar macros with tempest broke during logging in/out of follower dungeons (see if the area you were in or phased in was impacting the macro).