SmartSearch on Azure *was* working fine until a week ago, now each index that gets rebuilt (or new ones created) returns with:

Number of indexed items- 0
Indexed file size: 0B
Status: Ready
Last update and rebuild times are populated correctly.

The index folder in the Azure container shows the index name folder along with some files, one of which is MB in size

The creation/rebuild ticks along, taking roughly the same amount of time so things are happening.

Event Log shows no search index errors, just the expected UPDATEOBJ information events. Only error that appears is:

Message: Object reference not set to an instance of an object. 
Stack Trace: 
at CMS.GlobalHelper.MimeTypeHelper.LoadMimeTypes()

But a search on that index ALWAYS returns no records. It doesn't matter which part of the document tree I index or what smart search settings I use.

The only changes I have noticed is that Azure has changed the CMSTemp and CMSCache folder locations. They used to be under the D:\Windows\ folder, they're now under C:\Resources\. Other than that, no other clues.

Every new smartsearch index builds seemingly fine (except for the LoadMimeTypes exception but not sure if that's impacting or not) but always returns 0B with a status of Ready and no other error reported.