If I am reading their versions history correct the only MK3 users unaffected are the ones that have the oldest UTXOs older than 2021-01-14 when 4.0.1 version is published. So people that used MK3 can check in their Sparrow Wallet is their UTXO older than 2021-01-14 which means seed is generated with the firmware that generated normal entropy.

There is always a risk when having fresh channels on core lightning (Blockstream)