She is probably just scatty, and at least you have been invited - every time!
Not as bad as what happened to me once. I moved into a new area (moved away now,) and the girl next door to me (Lucy - 24 y.o with a 18 month old baby, and a 26 y.o. boyfriend,) was quite friendly with me, but way more friendly with the 45 y.o. woman next to me (Lyn.) (I was in the middle IYSWIM. Lucy was at House No.3, I was No 5, and Lyn was at No 7.)
Lyn - married, (with 3 teen children,) was like a mother to Lucy (at No 3,) as Lucy's mother lived 200 miles away, and she rarely saw her.
Lucy became quite jealous whenever I spoke to Lyn, and me and Lyn got on well, and she asked me round for coffee once or twice a month. Lucy looked furious when me and Lyn and her were chatting once (on the path,) and Lyn said she thought me and DH were the best neighbours who had lived next to them since they moved there 12 years ago (We were the 7th lot .. it was private let, we were staying there for a year or so because we weren't sure whether to stay in that area after we sold our house.)
Long story short, I took a gift for Lucy's daughter's 2nd birthday. (6 months after moving in.) I knocked on the door and handed it to her with a card (her birthday was the next day.) She said 'I am having a party for Lola tomorrow, so apologies in advance for any noise.'
No invite then LOL!
So the afternoon came the next day, and Lyn from No 7 trotted past our house to No 3, so did her 3 teens, and the 3 families from No 1, 9, 11, and 13 came past too. And the people from across the road (No's 2, 4, 6, 8, 10, 12, & 14. The whole neighbourhood in our cul-de-sac were invited.
Also Lucy's 2 cousins, her sister, and the 7 kids they had between them. And about 3 or 4 other friends of hers. I'm not gonna lie I was quite hurt. The only one left out.
I sat in my garden when the party was going on, as it was 30 degrees C and dry and hot. I sat at my patio table, up against our 7 foot fence between Lucy (having the party) and us at no 5. About half hour into the party they all came outside. 5 minutes in I heard Lyn (from No 7,) ask Lucy 'Where's Winterfell? Isn't she coming?'
Silence. Lucy obviously didn't have the balls to tell Lyn she had not invited us.
Five minutes later, a knock on our door. DH answered. It was Lucy.
I listened through the house, and heard her say 'errm do you and Winterfell and the kids fancy coming round to Lola's party?' (our 2 kids were late junior school age then.) DH said 'hang on' and left her at the door a minute. He came to me (I was in the kitchen by then,) and I said 'no.'
He said 'eh?' I said 'NO.' She decides to invite us to the party half an hour in. Fuck that. The kids were at their friends house, I had already defrosted what we were having for tea, and I wasn't being some fucking afterthought.
I never really forgave her for that tbh and was glad when she left the house a few months later (also private let) because the landlord was selling up.
Sorry about that rant. The OP just reminded me of it LOL!