I have problem with one song in downloaded TIM1&3 soundtrack. The song (from TIM1) is titled "Reggae". After one minute of playing, the song mutes itself. Rest of songs (both TIM1 & TIM3) works fine.

You might want to open an issue with Support about that, but after a bit of a look into it:
I think the headers in the MP3 are broken. This sometimes happens with certain MP3 files (ones with variable bit rate (VBR) encoding), and the only side-effect is that the track length is wrong.
If you put it on a playlist by itself and set it to repeat, it actually repeats quite well - it doesn't sound like anything is missing. I suspect that the song is actually only 61 seconds in length.
There is a MIDI file that sounds a lot like it (Even More Contraptions; sx_1037.mid) and goes for about 97 seconds, but I think it's actually a different version of the tune; it starts to differ from the MP3 around the 50 second mark.

The file size for that song suggests it's not supposed to be much longer than that minute - 1.64MB is a fairly plausible size for a VBR MP3 of one minute, and seems to fit reasonably well with the sizes and length of the other TIM1 tunes.
It's possible that it should be slightly longer than it really is, but it's definitely not the 5:45 it claims to be.
Winamp also states this when trying to edit tags for the file:
"MP3 has been modified from its original encoding. Some information may be incorrect."
It doesn't do that for any of the other files, so there's something different about this one, and that's almost surely what's causing the discrepancy.
There IS, however, an actual audio problem with one of the TIM3 songs in the soundtrack - Unplugged seems to skip a bit at 1:58.