MacBook Pro mid 2014 is offering to install Mavericks

The MacBook Pro (Retina, 13-inch, Mid 2014) originally shipped with OS X 10.9.4 (Mavericks). You can update it to Big Sur – but no further.

If you are booted into Recovery Mode and have selected the option to reinstall the original version of the operating system, the Mac might be trying to download and install Mavericks. Otherwise, I'm not sure where it would be getting Mavericks. Mavericks is the one version of Mac OS X / macOS between Lion and Sequoia (inclusive) that isn't available through this Apple Support article:

How to download and install macOS - Apple Support

Mavericks would not be an upgrade from Big Sur. Mavericks predated Big Sur by several years. Is it really offering to install Mavericks, or is it offering Monterey, which would be an upgrade from Big Sur though not, if you really do have a mid-2014 MacBook Pro, compatible. Why it would offer I can't say, though I have seen reports of Apple's upgrade system similarly offering upgrades that won't actually install. What model of Mac is the About This Mac Overview saying that you have?