One of what should be the ironclad rules of politics is that, despite protests to the contrary, party leaders invariably hate primaries. So, I doubt this is an intentional move. But this can definitely be very beneficial for the Republicans. After seeing the results of their defensive efforts on July 12, they get to adjust and go on the offensive. More importantly, voter turnout will be high for the big July 12 battle. But a month later, anger will probably have crested, the GOTV operation may need some R&R time, and turnout will probably drop.
By having a separate date, the Republicans could get the the anger and motivation shifting to their voters, especially if the lose control of the Senate in July. Since voter turnout is critical to recalls (with low voter turnout frequently helping the pro-recall side), this fact, plus a dog days of August date to depress turnout even further, could help prove very helpful for the three Republican challengers.
As with any primary, a bad candidate or bruising battle could devastate the party's chances of success. But the separate election date could be a difference-maker for the Republicans.