It is the expected result.

Both macros are castsequences, so neither can advance unless the spell in sequence fires off.
However, because of the spam nature, it is possible to get several clicks in a row from one macro or the other.

Of course, Lava Burst won't fire off while it is on cooldown, so won't trigger a GCD or advance... which means having several "2" clicks in a row is not detrimental.

As long as the "proc" macro goes off once every cooldown (approximately 8 seconds), it is serving its purpose.
Not as perfect as the click castsequences (which could be duplicated with Steps, if you wanted), but mindless and fairly close to optimal dps.