Received Conquest energy after it finished

I seem to remember something similar happened to somebody a few months back, but I can't find it.

I was absent mindedly opening Bronzium data cards in the store just after Conquest had finished.  When I looked down at my phone I saw that I had 2 pieces of gear (normal) and 137 Conquest energy.

Now, I'm confused as to what has happened.  

Did I open something else by mistake?

Has this happened to anybody else?

I forgot to use all of my left over Conquest currency.... it can't be a conversion as I can see it in the Conquest shipments.

Could it be (surely not) a bug?

Any thoughts are welcome please, as I hope I didn't click on something by mistake and spend crystals!

Yours in sport,

harvestmouse