Phone call from strange woman to boyfriend in middle of the night

I (F41) have been dating my boyfriend (M46) for 10 years, living together for 8. Last night he got a phone call in the middle of the night from a woman. I could hear her speaking to him. She said ‘daddy’ and his name. He asked who it was, she replied with her name. And kept saying ‘come over, daddy name, come over!’ He said he didn’t know who she and asked her name again. Then he hung up. The call lasted for a minute or two, so not too long.

I went back to sleep and didn’t think much about it, until I woke up this morning. I remembered what had happened but it almost felt like a dream.

While we were prepping for breakfast I asked him if he had checked out the phone number that called. I had assumed it was a spam call. He said he did, and it happens to be from a place he travels for work every other week. I said that was strange, and he proceeded to tell me it was from a caller with a name (caller id) and he wanted to figure out who this person was, that he was angry they had called in the middle of the night and woke us. He showed me the name, but I didn’t recognize it, it was also not the name the woman had said on the phone. So I asked him exactly what was said to him, and if they asked him his name, and he said yes, or if they already knew his name. He said they already knew his name and he didn’t need to confirm it. I also asked him if he recognized the name, maybe it was a coworker. His response was, he doesn’t know all of the employees that work with him.

I told him I heard her calling him daddy and asking him to come over multiple times. I didn’t want him to be able to deny what I know was said. But was hoping he could fill in some blanks. He looked upset that I had heard that. So I eventually asked him if there was anything he wanted to tell me. He said no, that he didn’t know who it was and that he didn’t know what to say to me. I should say I remained calm the entire time, I was not emotional or accusatory. But I said to him, would you not be concerned if roles were reversed? He agreed he would, and continued to eat. We have not spoken about it since. There is a definite awkwardness now. I know I’m feeling uneasy about this.

I don’t know what to do going forward. Do I drop this? Could it be spam? Or something I need to worry about in our relationship?