Is she being sneaky? OR does she like him and want to get with him on the low?

First off my so called friend knows exactly what time i go to school and it seemed like every time i go to school shes calling my boyfriend while shes at work and im not around, asking for me when she knows i’m in school, at first i didn’t think nothing of it because she WAS my friend and i trusted her , but then it kept happening and it would be the same time i was in school , then i started catching on , so when i did get the chance to talk to her i never asked her. but one day she just came out and said without me asking , that she calls his phone because the Job phone doesn’t work right and thats why she calls his number instead of mine, if you can call all 10 of his digits without it being a problem then you couldv’e called my phone and if you know im in school why are you calling him asking where im at and can you speak to me when you know damn well that im in school , to me that was Bs lie and i believe she felt guilty about it that why she came out and explained herself without me asking I’m just curious to know what she was trying to do , me and my boyfriend talked about it and i asked him what did he think she was trying to do .. and he said he thinks she was trying to see if he was gonna come on to her while i wasn’t around. Can someone give me there honest opinion on this or previous experience??? please & thank you Note: no nasty or smart comments , if you cant answer the question or say anything nice don’t say anything at all Thnx!!