Newbie shaman questions/Weird behavior on cannibalize macro and medding

[Hakubi]

I am level 25 troll shaman. Posting this here because it's probably just a lack of understanding in game mechanics or something stupid and doesn't look like it belongs in technical issues

I have been having issues with Canni dancing using a macro, I get random variations of mana return between 9-10 and the proper 20 when using the following macros as reported by DuxaUI's mana gauge:

/stand
/cast 5 (canni)
/pause 25
/sit

It more often than not returns 9 mana (while always taking 50 health) and vary rarely the proper 20. I have tried adjusting the pause from 15 <-> 30 and nothing fixes this behavior. If I manually cast Canni (manually sitting/spell gems either dancing or spamming) it gives the correct 20 mana. My meds tick for 12 every 6 seconds so... example:

Actual usage:
Starting mana: 200
Med tick: +12 (212)
Macro Canni: + 9 (221)
Sit in time for next med tick: +12 (233)


Expected usage:
Starting mana: 200
Med tick: +12 (212)
Macro Canni: 20 (232)
Sit in time for next med tick: +12 (245)

The only explanation for this is I am missing med ticks and the client acts weird until it gets server data... but my timing has to be right. Is this a client-server interpolation issue or me doing something stupid?

In a possibly related issue I always get weird behavior when standing after medding. I lose my last tick of mana (-12) after 6 seconds of standing unless I cast a spell immediately.

Ping is around 89-95ms. Latency meter says 100% except for the occasional drop into the 99.7x that corrects itself after half a second. There is a red star below it 100% of the time (no idea what that means).