Most synth issues on the Tracker+ can be curently attributed to the Macro Reset issue that is a known issue (see announcement for 1.0.1). Polyend themselfs have stated that they want to fix this as quickly as possible.
For now, if you encounter a synth that sounds weird, go to the Synth Macro Page (hit the Instrument Button twice) and reset all the macros (even if they appear at 0 or reset).