Old emails randomly scroll back several months while viewing current email.

There is a long standing bug in the iPad Mail App that produces the behaviour that you describe - typically due to resource exhaustion.

By design, it should not be necessary to manually close any open Apps. iOS/iPadOS should transparently and seamlessly manage its available resources as you switch between Apps and tasks.  That said, there appears to be a memory leak issue with all production versions of iPadOS 17 that leads to resource exhaustion in some circumstances. If issues occur, force closing unused Apps can usefully release locked resources to the system - and potentially alleviate the problem that you describe.

To expose the App Switcher page, swipe-upwards from the bottom edge to the centre of the screen, pausing briefly before lifting your finger from the screen; you will see a thumbnail image for each of your currently open Apps. Apps can be force-closed by swiping the corresponding thumbnail off the top of the screen.