I have been using RMarkdown for few years now and I never had issue running all chunks above at once using the icon below:

All of a sudden, "Run All Chunks Above" doesn't work anymore and I need to run chunks individually from the beginning every time. Thankfully "Running Current Chunk" still works. Even "Run All" or any other option using below doesn't work anymore.
Any help to resolve this issue would be appreciated.
Thanks!