Who the fuck uses an Iskander to target a group of friends and family in the middle of nowhere? Either there was some high-ranking Ukrainian officer at the funeral or Russia got shoddy reports that there would be and fucked up their target confirmation.

As far as terror attacks go, there are frankly much easier and much more impactful targets. As far as military targets go, there are far more strategic targets with lower risk of civilian casualties. A group of low-ranked military personnel and their families is hardly a high-value strategic target.

Something isn't adding up, so I think you're right and Russian intelligence fucked up badly. Corroborating this is that we've had no Russian confirmation of the death of whoever the target was supposed to be.

Edit: looking more closely at new reports, it really does seem like Russia fucked up bad. It's a completely disproportionate response to (from what I can tell) seems like a meeting of low-value targets in a non-military context surrounded by civilians.