Has anyone had or known anyone to have incorrect gender results from an ultrasound?

I'm in the UK and paid to have an early gender scan at 15 weeks at a private clinic, the sonographer was very confident baby was a boy, took about 1 minute for her to confirm it as it was so obvious apparently and I'm certain I saw boy bits to confirm!

We just went for out 20 week anatomy scan today at the hospital, the sonographer asked if we knew what we were having and we said boy of course. She did about a 20 min check of the usual bits for that scan and then at the end said I'll just double check the gender for you, and after 10 further minutes she couldn't confirm whether it was a boy, she said she wasn't convinced it was but baby had cord between its legs and was being a bit awkward. We just ended with her saying it kind of looks like a boy 🤷‍♀️

Now I'm panicking that maybe we aren't having a boy 🤷‍♀️ don't really want to fork out for another scan!

Can anyone advise / relate?!