background check - London

I’m a bit concern about something I wrote on my resume.

I interned for 6 months at a MM within a specific group, say, group A. Got a fixed-term contract after my internship to work with a IB team (think product team) along with my former team (group B). On my resume, I listed my internship with group A and my fixed term contract with group B as two distinct experiences.

My concern is that I have just sent the legal paperwork for my upcoming SA stint’s background check and noticed that legally, it is written in my contract that I did not work within group B. its written that I worked for group A to help group B on a specific project. Task description in my resume perfectly match what I did on the job and what is written on the contract, though.

Also, I slightly messed up with the dates in my resume: wrote that I worked 2 months on that fixed term contract while it only lasted 5 weeks. did not intend to, but i messed up because I had already started working for group B before my contract officially started. This mistake has been on my resume for a year now but only caught it now when I sent the paperwork.

looking for your perspective here - is it a big deal ? what do you think can happen ? I am not familiar at all with background check so idk what is the threshold in terms of inaccuracy/mistakes. Rest of my experiences (other internships, EC, etc) are spotless, if that matters.