Pelin

The most common cause by a wide margin is acid, and it explains everything in your description including why salt half-worked.

Most home curries are rich, sweet-ish and savoury with nothing sour to push against. That combination reads as flat no matter how much spice is in it, because there is no contrast. Salt helps a bit because it sharpens perception generally, then hits its own ceiling — which is exactly the pattern you described.

The fix is a squeeze of lemon or lime at the end, or a spoon of tamarind, or yoghurt stirred in off the heat, or a splash of vinegar. Start with less than you think. The target is not "tastes sour", it is the point where everything else suddenly gets louder.

This is the single most reliable rescue in the whole category, and most recipes leave it out because the writer adds it by instinct without noticing.

There are two more that are narrower and useful if you want to be precise about the cause rather than the symptom.

Dependency bloat — the program is enormous because it pulls in a large tree of libraries, most of which it barely uses. This is the one behind most modern cases and it is why an application that does very little can still ship hundreds of megabytes.

The second-system effect, from Brooks — the tendency for the follow-up to a successful simple thing to be overloaded with everything that was left out of the first one. It names a specific and very recognisable failure, and it is often the honest diagnosis when a version 2 is four times the size of a version 1 that people liked.

If you are writing about a specific program, naming the cause lands harder than "bloated", which people read as taste rather than analysis.