Hi boblite,
SoundTap will automatically create a new recording whenever a stream stops and restarts again. It does not do this based on silence detection as this can be unreliable and cause breaks where there shouldn't be any.
Some streaming services restart the stream for every track/song they play. Other ones just keep one continuous stream going. I'm not sure why you got two different results from the same source, but it seems like they were using different methods to stream on each occasion.
Regards,
Ben