@Dawn to dusk, out of curiosity, how did that loop work?
Clicking and cancelling while lagged (or just generally being faster than the server) would IIRC result in basically infinite quanta gain.
To add more clarity regarding abilities: All
activated abilities (be they on creatures or permanents)
do not provide a refund of
any cost involved in the card (be that quanta, the creature's life (in the case of virus), the HP gain (in the case of SoFo), etc). All
cards in hand do provide full refunds of all costs if cancelled before being fully played. Both of these items are working properly (though admittedly a bit counterintuitively).
Regarding the maxwells, are you
sure he didn't just damage it somehow (e.g. a chaos seed turning into a thunderbolt or whatever) right before using the maxwells?