Hmm... yeah, Rustler/Pest are becoming somewhat tricky cases to explain.
Rustler counts since it's using
to produce
- it's using 1 ability to interact with 2 quantum pools at the same time.
Pest doesn't count with the current rules because it's use/drain of quantum isn't in 1 ability -
Burrow and draining quantum are two different abilities. If it was something like "
: Burrow and generate
.", it could work.
So to summarize, the way I interpreted it, 1 ability has to do something to two elemental quantum pools.