CoreText garbles ligatures

Snapshot 134, macligatures is enabled. The font I am using is PragmataPro. It's hard to describe what I am experiencing, so let's have a look at two gifs.

Here is entering !== without CoreText:

As you can see, everything looks fine. Here is the same with CoreText enabled:

As you can see, something is quite off here. The ligature gets broken somehow during working on the line. However, when changing the line, everything looks normal. Obviously, disabling CoreText is a perfect workaround, but since scrolling performance is somewhat horrible, I'd love to know if there is anything anyone can do here to resolve this rendering weirdness.

Inizia riproducendo il problema con CoreText e macligatures abilitati, usando PragmataPro e inserendo !==; confronta il comportamento con CoreText disabilitato. Il lavoro è completato quando le legature continuano a essere visualizzate correttamente durante la modifica e le prestazioni dello scorrimento non risultano peggiorate.