How do you know he didn't raise his Shield right after the last of these happened? They were all in a span of just 2min, so it's kinda hard to catch him open in that case (which, IMO, is a flawed design; Shields should not work at least 1h after hitting anything).

This has always been like this.

You can't attack with shield up you will lose shield.

you can't send fireships with shield up you will lose shield.

you can't capture treasure Islands with shield up you will lose shield.

you can scout with  shield up.

you can send and recall reinforcements to a player with your shield up ( sending defence to a player blocked will liberate them if you send enough).

But you CAN raise the Shield right after all of your attacks have hit their targets.

If you are scouting or liberating you can put shield up before you start.