S-500 has been tested in Syria against the F-35?

via National Interest.

A defense industry source told Russian news outlet Izvestia last month that the S-500 recently underwent field testing in Syria, where the Russian Aerospace Forces continue to maintain a significant presence. The Russian Defense Ministry unequivocally denied that the S-500 was ever on Syrian soil in an October 2 statement, claiming that “there was no need” for further testing.

Despite the S-500’s imminent release, official specifications details remain as elusive as ever. Still, years of industry insider leaks, scattered developer commentary, and Russian reporting combine to give us a coherent picture of what to expect from the S-500. With a widely expected maximum operating range of 600 km and a system response time of 3 to 4 seconds, the S-500 reaches a whopping 200km farther and is around 6 seconds faster to respond than its S-400 predecessor. Underlining its strategic role, the S-500’s 77N6 and 77N6-N1 missiles can intercept hypersonic cruise missiles and ICBMs, as well as aerial targets flying at a speed of over 5 Mach. The manufacturer, Almaz-Antey, claims that the S-500 can even strike low-orbit satellites and certain types of spacecraft in near space, though it remains to be seen if the S-500 will face a performance trade-off when operating at such extreme altitudes. Formidable as it is in isolation, the S-500 can also complement existing systems such as the S-400 and S-300 by expanding Russian airspace and providing a further layer of defense against saturation strikes.

Unsurprisingly, the S-500 is being branded as a silver bullet against stealth fighters in general and the F-35 in particular. As previously covered by The National Interest, Almaz-Antey head engineer Pavel Sozinov asserted that the S-500 is a “blow against American prestige,” that “system neutralizes American offensive weapons, and surpasses all of America’s much-hyped anti-air and anti-missile systems.”

Story here. 

Don't know exactly WHAT is going on but something is.  WTF do I mean?  Well the F-35 has been sent to the Middle East but has yet to show up over Syria sporting the US flag on its side.

Either the Russian's air defenses are proving a deterrent, we're worried about giving away information on the plane or both is immaterial.

Something is keeping the plane out of the area and even with those stealth negating devices they slap on the fuselage they're still not participating in this war.