I do not remember this always being an issue - but on a new app i created my filters do not recognize equivalent entries when they are not typed exactly the same (ie case sensitive) Usually, we use a...
Glad I refreshed before replying... Slider covered most of it.
If you want to maintain both dropdown and spreadsheet import functionality, the best low-tech solution is going to be a helper field. I'd have the helper field enforce both trim and upper on the data entry field, and then use the helper field for reporting etc.
Except I think I disagree about hidden characters. First report I looked at in my app - it looks like in this context QB natively treats upper/lower case as in different alpha order! See my example: ARK... comes before Acu...
So, yeah, helper field, and hope your team doesn't mind all-uppercase. Goodness forbid that you are required to maintain mixed case styling such as AVnet.
Or open a support ticket and/or uservoice suggestion!