I found it bit curious, so I dusted off my detective hat. The rumour stems from de la Morena on his El Transistor show on Onda Cero, he had Florentino Perez on the show a week ago. So seems quite well connected to Madrid and the goings on.
Malaga coach Michel used to play for Real, called himself a 'Madridista' in public spat with Enrique. The chairman has got fined for calling Barcelona 'Catalan scum' a few months back. If clause only becomes active on July 1st, then it would account for delays but could also give Malaga motive to create panic and confusion. Atletico were already interested, and Real being interested would be more likely to deter interest you'd suspect. So not sure it would make that much sense and it doesn't appear to come from Malaga. Real wouldn't have needed to negotiated with Malaga anyway, given the release clause.
Rodriguez and Ronaldo are both going to be investigated over tax evasion on image rights and have decided they want to leave. Morata wants out to go and play football. Real signed only Morata last summer, when they were fined for transfers, they had a transfer ban in January window. Several players under investigation have decided they want to leave the country. It may be in Real's interest to set aside some money to contribute to legal defence or to pay fines with. While players are responsible for their own tax arrangements and accountable by law. Clubs have incentive to help get as much money to player after tax, as that's what most people look at and decide on, so they could well have more involvement and culpability than they would like demonstrated in legal proceedings.
Perez said that Mbappe might have to wait to play for Madrid, as it was a lot of money for a 18 year old who would sit on the bench. It not only reeks of entitlement, but it also pays a little homage to the fact that they couldn't afford their main target. It seems feasible to think that they were thinking about selling Morata + 1 and maybe getting Mbappe and Sandro, or have adjusted their plans after failing to get primary targets. Seems unlikely Sandro would want to go there, he said he wanted to score against them to win title for Barca only a month or so ago. He left Barcelona because he wasn't playing and didn't seem likely to get a chance, for a Barca fan its an entirely different prospect to go to Real than Athletico, even if he did want to stay in Spain.
Its possible that Real wanted to cover their tracks elsewhere in transfer market by putting it out there. I don't see him wanting to take all the damage to his Catalan ties for a small part role at Madrid. But it seems perfectly reasonable to think they are or were interested and don't want it known for fear of embarrassment.
Still a few days for madness to happen, but my suspicion is that interest was genuine and he is still going to join us.