How to troubleshoot a Lenovo laptop key taking ~5 minutes to start working?

I've recently started noticing an issue on my 2016 Lenovo ThinkPad where, when I open up the laptop after taking it out of my backpack and log in, certain keys don't work for a few minutes. I've noticed the Backspace and Tab keys seem to most-consistently have this issue, but I think also the 't' key and possibly other keys I haven't noticed yet (I haven't yet thoroughly checked all keys to see which ones have the issue). What seems bizarre to me is that once the affected keys start working, they seem to work totally normally. So I feel like it wouldn't be a hardware issue, but I don't know a

Question by Nathan Wailes on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.