Listed surface to surface mode for S300 is 120km.
Want some real conspiracy theory?
Two missiles means they were launched from the same site. Two missiles failed to self-liquidate is not very probable, means they had the SL system disabled.
Now, even if there was a Russian missile - they were launched West and let to fall whereever it would be.
Note, AFAIR S300 has a radio commanded self-liquidation, in addition to a built-in one on altitude and miss.
If there was only one missile I could've believed it was a malfunction somewhere. Not with a two.