“fft” ligature is broken in Libertinus Serif

[BrillanNording]

As can be seen in the screenshot above, the “fft” ligature is broken in Libertinus Serif when compared to Linux Libertine O. This is despite “fft” being listed among the “standard ligatures” in Libertinus’ documentation.

Steps to reproduce
Simply enter the character sequence “fft” into a word processor.

Expected vs. actual behavior
Expectation: all three glyphs combine into a cohesive ligature. Actuality: only the first two do.