Strange placement of the "tonos" above lowercase Greek eta in the Serif variant

[sykde]

In IBM Plex Serif, various diacritical marks above the lowercase Greek eta are placed unnaturally far to the left. Specifically, this problem seems to affect:

• Greek lowercase letter eta with tonos (U+03AE, ή)
• Greek lowercase letter and eta (U+03B7, η) with combining diacritical marks (e.g. U+0300, U+0301, U+0303)

This might have been intentional, as the tonos is also slightly offset to the left in the letter alpha tonos (U+03AC, ά), but unlike alpha tonos, in the case of eta tonos this feature is not persistent across other IBM Plex typefaces. Personal bias: It also looks strange...

In IBM Plex Sans, the tonos in eta tonos appears in the "normal" spot, near the middle of the letter's width.

The fonts affected seem to be all the variants of IBM Plex Serif. For the tests, only TTF files were used: IBMPlexSerif-*.ttf (Version 3.0.0, sfnt Revision 3, Release v6.3.0).
All tests were done in Windows 10/11, in Microsoft Word (Verson 2311, Build 17029.20068) and in FontForge (20230101).

[BoldMonday]

The placement of tonos to the left on eta in Plex Serif is intentional, and was advised by Irene Vlachou who consulted on the Greek design. Granted, Plex Sans has a slightly different approach. We might fix that in a future update.

Occassions where eta will be combined with Latin diacritics such as U+0303 are unknown to us, and therefore were not considered.

[sykde]

Since this was confirmed to be an intentional feature, I will be closing the issue. Thanks for the clarification!