Ingest is buggy? I get different results on different days from the exact same JSON

Example:

303 items ingested successfully
08/15/2022 11:01AM

4 items have error: Thumbnail could not be downloaded.

Now, without changing anything on the server side (same JSON, same media, same poster images - literally nothing has changed)

288 items ingested successfully
08/17/2022 11:02AM

19 items have error: Thumbnail could not be downloaded.

How do we get to a log file? What are these errors? Why could not the thumbnail be downloaded?

Note: All our videos have a poster image. Server side we generate a 1920x1080 black frame and center/scale the medias poster frame into it & the endpoint for the image URL hits code & that result is cached.

What we can’t do is see a log file, what the actual errors are & figure out what Roku ingest is tripping over.

This is cray-cray - how do y’all deal with this?