Mmm. I believe I found a bug. Yeah!
So I have an item that extends the limit of the project. I believe it did after I have changed the max viewable length of the project in a Project Settings / Advanced
The length of the item reads "-2147483523.0.50" in the Item properties.
Maybe this weird value was set when I changed the "Project Settings / Advanced
[✓] Limit project length, stop recording/playback" setting
This item which expands over limit does NOT play at all, until I change the length to a value like 10 (which brings the end within project boundaries)
Thanks devs!