Using only immediatelyfast 1.13.2+1.21.10 with the experimental sign text buffering (https://mclo.gs/YCOaEtT).

When i write some emojis on a sign, like ✍️ this is the result:

This is another example (left with the option right without)

Duplicate of #117

TL;DR: Its pretty difficult to fix this, due to the way the optimization works. I might look into excluding signs, which contain non ASCII characters when I have time to work on this optimization