what is this on underside of leaf?

We have grapes covering our entrance arch.
I noticed this the other day, see picture.
What is this and how to treat?
Thanks
James

Could we also see the top side of the leaves and how they appear on the plant?

here you go.

I’m not great with grapes…assuming those are grapes or?  Are you watering at night ?  

I’m not seeing insects..are you?

Water very early morn about 5am.
Did not see any insects, just these brown spots.
On the top the spots are raised, underneath they are concave.
Not really close to the grapes at this moment.
It is getting worse though slowly.

My first thoughts were that they are Galls but when I looked gall up they were raised and yours didn't look raised.

Now you say they are raised so that might be what they are.

The gall itself is the plant’s response to the irritation. It’s not unlike the bump you get when an insect feeds on you, except the leaf gall is not going to go away

https://www.thespruce.com/dealing-with-leaf-galls-1402697

As unsightly as they are, the best thing to do is just let them be. Since the damage occurred before the gall formed, treatment is rarely recommended.

Anne,

If it was gall would it continue to spread?

Thank you.
Good to know, if it starts to get really bad I will have to try and figure out what kind of insect is causing the damage and take appropriate action.

The only time I have seen galls was years ago on a friend's trees.

I was young and didn't even ask what was wrong with the trees.  My friends were unconcerned.

It can be caused by other things damaging the leaves.

If you see insects you might use a diluted soap spray though if they were my trees like that article said ... treatment is rarely recommended.