whistle control

 May be a proto2 board issue, but till one of the MTH gurus chime in; Check your track to track connections at the "bad spot" for a weak rail in that section yet? Is the problem direction based? Happening both directions if the loco is faced both ways? Swap position of the offending track with another piece. If the issue follows the "bad" track, its a bad section.

Typically, it's a symptom of a low DCS signal issue or more than one connection to a track block.

Regardless, it's very unlikely that it's a problem with the engine's electronics.

If other PS-2 engines don't do it, but this one does it still could be the engine electronics.  The Power Supply board may have an issue and degrades or doesn't process the DCS signal well enough.  When using this engine do a signal strength test.  Compare it to your other PS-2 engine.  G