We've been having big problems in our multi-server environment with the Find indexer not always indexing one or all properties of a document, or not at all. It seems to be isolated to the event based indexer, the scheduled job always indexes everything correctly. Trying to re-save the page multiple times some times helps, but most often not.
It's been working OK on the production and staging servers but the testing servers and the local development servers have been more or less impossible to work with, find-wise.
Find has given us no errors in the logs, and even a custom serialization trace writer more or less says everything is OK when it's not.
I finally tried to set ContentIndexer.Invisible to falseas per this answer on an old thread, and it seems to be working (still might be too early to tell but looks good so far). The docs say this setting forces the indexer to run in the shared event thread and not its own (it's true by default).
Does anybody know something about this and why it's happening and if it could be related to something else and not the thread setting? Can't seem to file a support ticket right now. Anyway it might help anyone else having weird indexing issues.