According to El Universal, Tijuana's board now accept a move is only a matter of time, and are said to be setting the clause at around €21.3m - a figure the Mexican outlet claims both Liverpool and Arsenal are already prepared to pay.
Interest in the 17-year-old has been building throughout the World Cup, with Manchester United, Chelsea and Manchester City also credited with tracking his progress alongside the two Premier League rivals.
There is no indication yet of when either Liverpool or Arsenal might move, though El Universal presents both as the clubs best placed to meet Tijuana's valuation once the clause is formally in place.
The figure marks a striking change from earlier reports. Just days ago, Tuttomercatoweb suggested Tijuana were holding out for closer to €40m, with Manchester United, Chelsea, Bayern Munich and Real Madrid all mentioned as suitors at that price.
El Universal's lower figure specifically refers to a release clause being drawn up rather than a simple asking price, which may explain the gap between the two reports.
Whether Mora's eventual fee lands closer to €21.3m or the previously mooted €40m remains to be seen, but the volume of interest from Europe's biggest leagues suggests a move abroad is now viewed as inevitable on both sides of the negotiation.
The teenager has been one of the standout performers to emerge from this summer's tournament, drawing praise for his composure and range of passing from a central midfield role well beyond his years.
Tijuana, for their part, appear to be preparing for the financial reality of losing their prized asset rather than resisting it, a shift in stance that suggests talks over a permanent exit could move quickly once the release clause is formally confirmed.
For Liverpool and Arsenal, positioning themselves as the frontrunners at a lower valuation than previously reported would represent a notable coup, particularly with rivals from Spain, Germany and Italy already known to be aware of the player's situation.