WowAce

1x Quartz\modules\Player-Player.lua:235: attempt to index upvalue 'channelingTicks' (a boolean value)
[string "@Quartz\modules\Player-Player.lua"]:235: in function <Quartz\modules\Player.lua:230>
[string "@Quartz\modules\Player-Player.lua"]:257: in function `UNIT_SPELLCAST_START'
[string "@Quartz\modules\Latency.lua"]:113: in function <Quartz\modules\Latency.lua:112>
[string "=(tail call)"]: ?
[string "=(tail call)"]: ?
[string "=(tail call)"]: ?
[string "=(tail call)"]: ?
[string "@Quartz\CastBarTemplate.lua"]:264: in function `?'
[string "@Quartz\CastBarTemplate.lua"]:129: in function <Quartz\CastBarTemplate.lua:127>

Locals:
spell = "First Aid"
(*temporary) = false
(*temporary) = "attempt to index upvalue 'channelingTicks' (a boolean value)"
db = <table> {
noInterruptShield = true
h = 25
nametextx = 3
noInterruptColorChange = false

100% happens when bandage

+1 to confirmed, this reproduces 100% of the time. 

+1 for bandage, this also happens when channelling Drain Soul or Life and Fishing, so any 'channelling'

As a work around you can use the below to prevent the error popup;

/console scriptErrors 0