It's probably just a generic error message for failing that Google Play Protect thingamajigger that attests provenance of the vendor OS from boot. Will be interesting to see whether the Motorola phones have this endorsement when they ship. Most devices would probably fail because they are rooted rather than because they are GrapheneOS. I wouldn't put it past a scammer talking grandma into rooting their phone.
It's probably just a generic error message for failing that Google Play Protect thingamajigger that attests provenance of the vendor OS from boot. Will be interesting to see whether the Motorola phones have this endorsement when they ship. Most devices would probably fail because they are rooted rather than because they are GrapheneOS. I wouldn't put it past a scammer talking grandma into rooting their phone.