you need to exam the option chain.
it could be arbitrageur doing arbitrage(synthetic).
or might be aggressive activity from INFORMATIVE trader, which will
in turns fluctuating/propagate to the whole chain on illiquid symbol
as market marker needs to hedge.
or it could be covered write or buying put or spreading from institutions.
Personally, it takes me quite some time checking those chains with high %
change in terms of volume.