I thought that the minimum amount was 0.0001 these days, but I'll occasionally receive an amount under, like 0.00006. I thought dust transactions weren't processed any longer, even with a higher fee. Is this not the case or did something change?
I don't think the "minimum amount" has ever been as high as 0.0001 BTC.
The "minimum amount" of 0.00000546 BTC is only a minimum in so far as most peers won't relay the transaction and most miners (and mining pools) won't confirm it. However, if a peer wants to relay the transaction and if a miner (or mining pool) wants to confirm the transaction, they still can. They aren't stopped from doing so. Blocks that contain such transactions are still relayed by all peers and are still considered valid.