It would be better to wait for Mercury turning direct, at the end of August. But if you can't wait, as you risk to loose this opportunity, if you apply just make sure that, in case of being hired, you sign papers and contract when Mercury is direct to avoid misunderstanding.
Well, I once signed papers for a job with Mercury rx. After a few months I chamged job as it was not good for me BUT there was a misunderstanding about retribution. At the end, I received what I was supposed to receive in terms of money, but this required a sort of fight with administration, and lead to the end of this job. Economically positive, but negative for the job. But I changed job immediately after with a different kind of employement, that was my desire. So all of this caused misunderstanding, loss and gain, and change of things.
If applying to this job represnts a change to your usual patterns, then Mercury rx would be appropriate to help change something in your life, but keep in mind this may happen through confused circumstances.
It's also possible that nothing happens, as Mercury rx does not affect everything (not every car crashed or every computer malfunctions! Energies manifests only in some cases with negative outcomes).