[DanCooper]

I'm new to both Kodi (17.3 Krypton) and Ember (1.4.8.0-alpha23.3 x86).

Neither Database Update nor Reload All XY nor F5 change something on NFO or other content. All three methodes read only the local stored files. There are only two exceptions:
- If YAMJ watched file is enabled, the scanner compairs the watched file and NFO if both has the same watched status (but that is only YAMJ releated)
- new episodes will be scraped automatically if no NFO exists

So my question is: how to you've edit the NFO after scraping? If you've done it manually you have to reload the movie with F5 to read the NFO and save the new information to Embers database. Otherwise Ember will overwrite your NFO with the information that Ember has in the database if you scrape or edit a movie.
The other thing is: Ember reads only known XML nodes. Costum nodes will be overwritten if you change something in Ember. So why do you not use the Edit dialog?

I use the editor, but was not aware that I should hit F5 to make the edited data enter in the database.

I did the following:
Noted that an entry had both TITLE and ORIGINALTITLE.
Double-clicked to edit and removed TITLE.
Hit OK then hit F5.
The TITLE (which I suppressed) reappeared!
How to assure that edits are maintained and entered in the database?

The point is: Ember needs a Title.
While scanning the database (F5 or adding to database while DB update), Ember reads the NFO if it's exists. If no title available in NFO, the scanner detect the NFO as "invalid" and set the NFO-path to "not set" (that means the information has been loaded to Embers database, but the NFO will be set as "not existing"). At this point Ember try to get a title from path or file name, depending on your source settings.

The reason for this is, that "Original Title" is only optional and the "Title" is required. In your case that means you've to set the "Original Title" as "Title" if no title can scraped or no title is known.

ATM it's possible to remove the title in Edit dialog. I think I've to fix that to remove the possibility to close the dialog without a title has been set.