Most likely ISIS used gear provided to "freedom fighters" or the Iraqi Army re-target the strike.
The fact that ISIS captured such gear has been published even if it was buried well off the front page. Both the Iraqi Army which abandoned or lost a ton of equipment as well as for the "good freedom fighters" not long before those "good freedom fighters" switched sides and joined with ISIS. There's no doubt ISIS has required equipment and expertise to divert an incoming weapon.
The Russians want ISIS dead and gone, not NATO/US forces becoming even less effective at hitting ISIS.
Everyone not drinking the Kool Aid can see that the US and NATO backing Muzzie scum all over the ME has disastrous results. No one needs to frame them for anything. They've done more than enough to make themselves look bad already.
Unfortunately people in this country have become so used to childish narcissists running the country that they believe any and all propaganda and fall in line blaming anyone but the Kiddies in charge when something goes wrong. Some folks have their heads so far up their exhaust port they even jump to conclusions like blaming the Russians for this sort of mistake even though the exact same sort of thing has happened in every conflict NATO/US forces have been involved in since Kosovo.
Any of this sort of mistake that happens isn't "spoofing", it's the usual blow-back from insane operations that support murderous Muzzie scum to further the economic ends of turds that support the likes of King Barry.
You make a good point that captured gear could also be used to re-target that airstrike.
Adds up, don’t it.