Opentype Feature that won't break while modifying Spacing in Indesign

I’m designing a monospace font… and the idea behind this code is to get a kind of ligature, while still allowing spacing modifications in Indesign,…

My OT-Code is:
sub i’ m by i.narrow;
sub i.narrow m’ by m.wide;

The Code works fine. Besides that Indesign seems to deactivate all opentype-features when I increase the Spacing over 38 :confused:

Any Ideas?
THANKS in advance…

I forgot to mention that I already tried: liga, calt and aalt - nothing worked yet.

InDesign deactivates alternates at +32 spacing. What’s the rationale behind the massive spacing?

I haven’t tried it, but you could put it in the locl feature, right after “script latn;”

worked perfectly. thanks mekkablue!