[micahg]

I observe that the imdbnumber for a show changes depending on the system. For my laptop (ubuntu) and my mi box (android), for example, "The Good Fight" has an ID of 69158.  However, on my firestick, the same show has an imdbnumber of 320766.

I think your firestick is right and the other two are wrong. If I do a search on tvdb for 320766, I get "The Good Fight" and the search for 69158 gives no results.
I would suggest re-scraping the folder with the media and settings debug verbosity in the advanced settings to high, to see where the wrong number comes from.  

Thanks @schapplm ,

I dug into this a little further. The firestick was, for reasons unknown to me, using a different database: The Movie Database (tmdb).

Those id's are provider specific... maybe that isn't a great key to use -- or maybe we could do a secondary match on name if we don't find a match on imdbnumber.  I had a look at the JSON RPC code, and although the kodi db tracks where the id came from, json rpc doesn't expose it. My initial though was that perhaps we should include that along with the show id.

We could probably submit a patch to expose it if we can't think of a better way to correct this in the addon.

Did we always use the json rpc or did we used to go right to the db files with sqlite?