DIAGNOSIS The taste is from the new food-grade plastic components and tubing inside the machine. It needs a prolonged flush, not just the short clean cycle.
FIX Do not use chemical cleaners. Fill the reservoir with a 50/50 mix of white vinegar and cold water. Run a full clean cycle. Discard that vinegar water. Now, fill the reservoir with fresh cold water only. Run the machine through 3-4 complete ice-making cycles, discarding all ice produced. This flushes the entire system.
IF THAT DIDN'T WORK The charcoal filter in the water reservoir (if your model has one) is saturated or was not installed. Check the reservoir lid or base for a small filter cartridge. Remove it and run the machine without it. If taste improves, replace the filter.
HEADS UP The first 24 hours of use will always impart some taste. This is normal. Always use cold, filtered water if possible. Warm water leaches more plastic taste.