Did you swap any elements of the rune bolt casts?
I half recind this question. Since i guess your LLC and CLC example are all runestone procs?
I swapped fire and cold to lightning. The runestone seems to still have the FLC cycle even though I am all lighting which should be LLL. Resulting for example in the following (Caps are runestone procs):
F l l l l C l l l l L l l l l F l l F l C F L C l l l l L l l l l F…
The difference in lower case l’s indicates different cast timings.
if you changed elements. It could seem random since the cycle isn’t obvious on non runestone casts.
My question would be if this behaviour is intentional. It kinda annoys me since I want a reliable L proc.