It does not taste like the fruit
Updated
The process half
Flavor is lost at heat and the loss is cumulative, so the causes here are all about how long the fruit spent hot rather than how hot it got. Batch size shows up again for the same reason it does everywhere else.
Scorching is local overheating at the bottom of the pot, and it is a function of depth, heat and stirring. The guide specifies stirring to prevent scorching during the simmer for exactly this reason. Once a batch is scorched the flavor is in it and cannot be taken out.
The buying half
Some flavor was never there to lose. Fruit bought underripe for firmness, or out of season for availability, puts a ceiling on the finished product that no technique raises.
Poor quality fruit makes poor quality preserves, and no amount of process recovers it. This is the argument for buying on condition rather than price and it is on sourcing fruit.
The one that is neither
There is a third cause that is neither process nor fruit, and it is the one people least expect because it happens after the jar is closed. Flavor keeps moving in storage, and a warm store ages a jar faster than the calendar does.
A product that tastes of sugar rather than fruit, with nothing scorched and good fruit in it, is usually a ratio problem rather than a flavor one. The fruit floor in the standard is on the ratio the standard sets, and 45 parts is a minimum rather than a recipe.