Mild chickenpox after one dose of CP vaccination?

[MyNameForToday1980]

DD had the first dose of the CP vax just before the start of COVID. We didn't get around to the second dose as the world went a bit wild.

Yesterday she had two very poxy looking spots on her torso, today she has five.

Not crusty. But notably poxy.

She is otherwise a bit grumpy, but fine - no fever, no pain, slight itching (she's 4, and has been in a cantankerous mood for a few days).

Has anyone had any experience of very mild chicken pox having had half the vaccination?

Or, can you think of a reason she'd have five slightly itchy pimples on her chest? (No allergies we know of, but dry/sensitive, slightly eczema-prone skin). I'll upload a photo in a mo.

Here are a couple.

PS I don't think the vaccination caused them obvs, as almost a year has passed :-)

My son wasn't vaccinated but when he had chicken pox he literally only had 3 spots on his back. It was diagnosed by a doctor.
It could be chicken pox or possibly insect bites? Are they itchy?

They are a bit itchy, mainly at night, but not bothering her a huge amount.

I can't think of any insects she'd be likely to be in contact with (no pets) and I haven't seen any midges around.

Maybe spider bites, but I can't imagine a spider coming back the following night for another nibble.

I just googled breakthrough varicella, and it does look a LOT like the mildest image here :

WARNING THERE ARE SOME AWFUL CASES OF CP ON THAT LINK:
www.cdc.gov/chickenpox/about/photos.html

Same thing happened with DD. With a lot of initial vaccinations you don’t get a full immune response with one dose.

My chicken pox didn't work unfortunately. I had two doses and a serology test after to check my immunity and I didn't have any antibodies.