Are engineer's sandbags now invulnerable to tank cannons?

So I’m playing in my LVT in the Pacific, I see sandbags (not hesco) behind which clearly there is a rally point since dozens of Japanese soldiers pop out there, but when I try to shoot my LVT cannon at the sandbags to destroy the rally point behind them, the shell does nothing?

I remember the sandbags were buffed, but were they maybe buffed too much?

Low caliber HE stuggle more to destroy sandbags