Spotify [Triode] problem: Frequent bufferunderruns

Since about a week, I have an issue with streaming Spotify to my
Squeezebox and iPeng players. The issue occurs only with Spotify; all
other streaming services work fine. Also, Spotify works fine when using
the PC Spotify client.

The problem is that every few seconds, playback stops (hardware players)
or starts stuttering (iPeng) for a second or two. The hardware players
indicate that rebuffering is in progress. After a while, the player
seems to give up on the current track and moves on to the next one, with
the same problem.

I have upgraded to the latest version of the plugin, to no avail.

The plugin's self test completes without errors (including the streaming
to device test).

Every now and then, I see suspicious messages in spotifyd.log, including:

[17:16:49.067131] main:816 existing streaming connection exists - killing

[17:17:29.606936] main:1579 relogin requested
[17:17:29.607128] main:1608 resetting streambuf

[17:19:34.094124] music_delivery:564 error writing
[17:19:34.094265] main:1608 resetting streambuf

The last message seems to be most closely correlated to the buffer
underrun problem.

Any advice please? Thank in advance!