Bug/Issue Heart Jump

Today I decided to give Abigail an Amethyst, because I only had her at one heart and was trying to get everyone to two. She took it nicely, and I moved on with my day.
Then, I was passing by Leah, who I also only had one heart with, and all I did was TALK TO HER. All of a sudden I got an achievement, and went to look at what it was: Gain 5 hearts with 4 villagers.
I thought that was odd since I swear I only had a few people at around 3 hearts besides Haley and Demetrius.
So, I opened my social tab and found out that Abigail and Leah were now at 9 hearts each...
I tried to recreate this with Pam by just talking to her or gifting here (as she was also at one heart) and it didn't work.

Summary: Hearts jump on villagers drastically when all I did was talk to them or give them one gift.
Expected behavior: Relationship to go up slightly.
Actual Behavior: Relationship jumped up 8 hearts each.
Steps for Reproduction: So far, talk to Abigail or Leah or give them a gift.

Edit: This also just happened with Sam as well. But I did have 3 hearts with Sam.