What a horrible design decision. Instead of making a system that simply works or doesn't work Microsoft allowed everyone to produce apps which break at random times in the future. It's one of those "what could possibly go wrong?" cases.

Is there a default, or standard TTL for this type of certificate?

EDIT: Looks like the standard TTL for these code signing certificates is none, 1, 2, or 3 years.

https://www.entrustdatacard.com/products/categories/digital-...

https://www.globalsign.com/en/code-signing-certificate/

https://www.instantssl.com/ssl-certificate-products/code-sig...