Options don't save on exit and won't open last saved/edited/opened

Check version

• I'm running the latest version of Path of Building and I've verified this by checking the changelog

Check for duplicates

• I've checked for duplicate issues by using the search function of the issue tracker

What is the expected behaviour/value?

Changes made and saved in Options, like using thousands separator, should save and be set next time POB is opened.

POB should default to last build opened/saved on open.

What is the actual behaviour/value?

Any changes made and saved in Options, like using thousands separator, will not save on exit. It resets every time I re-open POB.

Back in 3.14, POB would open to the last build I saved. It didn't do it in 3.15 and it's still not doing it now. It keeps defaulting to a build from 3.13 that I haven't opened/used since then. I thought this would be fixed in 3.15, so I didn't report it until now.

How to reproduce the issue

No response

Build code

Build POB should be opening to: https://pastebin.com/yWC03DPW (build I'm currently working with)

ALWAYS opens to https://pastebin.com/2WQALZtf since 3.15

Screenshots

No response

Start by tracing how Options changes are persisted on exit and how the application selects the build opened at startup. Reproduce both failures using the reported expected and actual builds, then verify that option values persist and the most recently saved or opened build is selected.