That didn’t sound like a mortar to me. Sounds like a propelled projectile. Could it be there was a drone nearby?
Flash to bang time says it’s probably an RPG.
Good point. I had not noticed previously but the whooshing sound does sound more like an RPG incoming or perhaps a rocket or missile strike. The vid is listed as a mortar strike on the youtube site, so I simply repeated it in the headline.
Nice catch.