i got shielded myself today with 24 hours shield 3 min later i was attacked and got taken 30 points. this shouldn’t be possible, right?
A few others have reported it, I don’t think there has ever been a definite answer on how it can happen.
Some speculate that you can take a loss and there was a bit of lag in recording it to the server. So, when the server compares the timestamps of your loss and your shield time, it makes you lose the points because the match ended before you shielded.
i thought so but it was not short in between. really strange. i wrote mail asking d3 to add back 30 points i have lost. thanks for answering
Maybe its like in other online strategy Browser Games. A shield can protect you from following battles But not from battles which are already in Progress.
Here IS an example:
Adam Starts Battle with Bea at 7.30pm
Bea Uses a shield at 7.32pm
Adam Win and finished the Battle at 7.35pm
Bea lose the Points because the Battle was already in Progress
Just my opinion 
Greetings
90% not true. Its usually only seconds after You shield when You start seeing attacks resolved.
As for OP - happened to me as well, but it was something like a minute after I shielded. Lag probably.
i got points taken away from me after being shielded for 5 min i lost 30 points. no sense