Question

I try to tithe from the money I earn.
My wife was walking in a fairly deserted forest near the community, and there is a road there that people once used to drive on, but nowadays maybe one car a day passes there, if that.
She took her cellphone out of her pocket and didn’t notice that along with it, two banknotes came out too 💸 and flew around the forest for their own enjoyment.
A few hours later she reconstructed where the money might be.
She said maybe it’s still on the road in the forest, let’s drive there.
I had pretty much given up, but I was happy that this time it was only two bills and not, again, the whole wallet with the documents, credit cards, etc… as is their way of getting lost.
But we drove there, and lo and behold, despite the winds, it was quietly waiting for us at one of the bends in the road.
Is that considered newly gained profit, so that I need to set aside tithing from it?
Or since this was money that had been in our possession and was lost, but it is ours and had already been tithed, is it exempt from tithing again?