Tracks missing after Spotify -> Youtube conversion

Hello, just loaded my master playlist from Spotify (1871 tracks). Conversion to YouTube seems to work for all tracks, as the converter loads and display a YouTube track name next to the imported Spotify track name for each track during conversion progress. Issue comes up when I hit the "save to YouTube" button after conversion.

The issue is:

• Only 1250 tracks are in the playlist when I load it in YouTube.
  How can that be and are there any solutions to get all 1871 tracks into the YT playlist?

• 1250 seems to be a conveniently even number. Am I hitting some API limits with my conversion?
• Am I maybe facing GEMA issues since I'm in Germany? If yes, how to circumvent possible GEMA blocks while using the converter?

Update: Did the conversion run again and notice the following:

As said, Spotify list has those ~1800 tracks. During conversation I see:
Converting tracks !!! 149 on 1389 tracks

• Already here some tracks are missing. However, after conversion run is done, it shows a total of 1932 tracks before I export to YT.

Here's a paste of the generated output before saving to YT.
https://pastebin.com/fBzSxVqs

So to summarize:

• 1871 tracks supposed to be loaded from Spotify,
• 1389 total shown in the converter's progress bar
• 1932 actual tracknames converted as per above output paste
• 1250 saved to youtube.

Something is wrong here, ain't it?