Just tested with enjin which is also quite large. Unfortunately they are also going off-standard - their ERC-681 looks like this:

ethereum:0x2E9F06153Ce4bf5cCE30bf18C1BA1899B50A18Ea?token=ETH

dropped them a mail and invited them to the ring - perhaps it would be good if more people write mails like this. They might ignore a single mail - but they cannot ignore us all

support@enjin.com