A student received an industry job offer contingent on having completed his Master's degree by his July start date. If he has completed all of his coursework and has a signed thesis by July, but the degree is not issued until August or December (because the school only issues degrees 2 or 3 times a year), should there be a problem? His advisor is willing to provide him with a letter stating that he has completed all of his degree requirements.
I had the same condition on employment once. I completed my course work and even walked in the ceremony but there was some paperwork that needed to be done somewhere. Not on my end, but still it meant when I walked I got a blank diploma in the folio.
To this day, I have still never actually received my degree. It's been 7 years. And no one has ever been like "hey corsiKa, you don't have a piece of paper on your wall. Did you really get your degree?!" Yes, of course I did. And the paper is really meaningless anyway - if someone truly wants to hold your feet to the fire, they'll send for an authorized transcript with your current status.
As professionals, we tend to take people at their word for common things like that unless and until it becomes apparent that it might not actually be true.
Most universities will hand out diploma holders during commencement (graduation) ceremonies that contain a sheet of paper instead of an actual diploma. This paper usually says something to the effect of "upon verification of satisfactory completion of all degree requirements, your diploma will be mailed to you in 6-8 weeks". This is the case when graduating in a semester that traditionally includes diploma issuance (such as May in the USA). The effect is magnified when graduating in an off-term, such as the Summer, when the next graduation ceremony may not be until Winter.
Employers are most certainly aware of this and if they hire new graduates they probably have experienced it many times. You should note that technically the student may not have formally graduated, as I have experienced when a family member completed their doctoral program and needed state licensure to begin practicing and the state would not grant the license until the diploma was formally recognized by the university. For simple employment, this will likely not pose any issue and the most they would reasonably ask is to present the diploma or an official transcript once it's available in a month or two.