The re-load is not likely to help with a MSP4 keyboard issue. I had this same issue in October of last year (see pages 45-47 of this post) I do not have much hope of Microsoft correcting the issue. I do not think they know what it is.
I went through all of the diagnostics, repair installations, cleaning contacts, etc. that are posted in this thread and several others with no success. I finally took it to the Microsoft store.
At the Microsoft store, the agent spent about 2 hours trying to fix it. They only solution they could offer that would allow me to continue to use my computer, was to purchase an aftermarket (third-party) bluetooth key board. They gave me a list of possible keyboard options.
An example is here: https://www.amazon.com/MoKo-Microsoft-Lightweight-Bluetooth-Rechargeable/dp/B017TU3DVQ
In the edn, since the unit was out of warranty, they did give me a discount on purchasing a new unit. I opted for purchasing a new MSP7 unit, since I already owned all of the accessories.
As a side note, having had both the MSP4 and MSP7, I noticed that all of the odd quirks that the MSP4 had were all gone in the MSP7. I am now convinced that the MSP4 was never right. The keyboard issue was just the last straw for the MSP4.
And, sadly no, Microsoft will not respond. It appears that they are steadfastly ignoring this thread....